text:
Talk:Becoming a Private Pilot

New title
The book title is not very descriptive. Might there be a better name you can think of? - Aya T C 22:03, 11 August 2005 (UTC)

 * I've renamed this book to "Becoming a Private Pilot". - Aya T C 22:12, 11 August 2005 (UTC)

Sounds good to me -ppragman

 * I've also fixed your Wikipedia links. Have a look at WB:NP when you want to create subpages. If you need any more help, drop me a message on my talk page. Thanks. - Aya T C 22:22, 11 August 2005 (UTC)

If this article is to be of practical use, I recommend that the focus be placed primarily on more generalized and academic private pilot information as opposed to specific procedures, as someone who has not yet begun their training as a private pilot will little context or use for such information, while someone who has already begun their training should have access to more accurate and reliable sources. --67.123.165.163 02:20, 14 August 2005 (UTC)

all right, i'm going to revise it all a little as we go, but eventually, i'd like to have created a resource on the web that could give you all the stuff they put in those expensive training books, for free! I dunno, maybe it won't be that easy. Should I make a table of contents to organize this stuff, or should I simply remove it? --ppragman 8:39, 14 August 2005 (AKST)

 * No point in removing it. It's still good content. - Aya T E C 17:38, 15 August 2005 (UTC)

Many public, free sources of information about learning to fly are already available, especially for those who want to earn a pilot certificate, add a rating, or learn more about flying in the U.S. For example:

For information about learning to fly, see:

AOPA Learn to Fly page: http://www.aopa.org/learntofly/)

AOPA Flight Training Learn to Fly: http://flighttraining.aopa.org/learntofly/ Be a Pilot: http://www.beapilot.com/indexfl.html

The FAA offers many complete, public-domain training handbooks for free download in PDF format. These books are the official references for many pilot certificates and ratings. You can find the current list at: http://www.faasafety.gov/onlineresources.aspx?categoryId=47&masterId=1

The following books available via the previous link are of particular interest:

The Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25) is for aviators training for a private pilot certificate-and for pilots who want to refresh their knowledge of the fundamentals. It introduces pilots to the theory and practical knowledge they will need as they progress in their pilot training from aerodynamics, engines, flight instruments, and navigation to avionics, weather, and airspace.

This 352-page handbook is available for download in PDF format in four parts (Part 1, Part 2, Part 3, and Part 4).

http://www.faa.gov/library/manuals/aviation/pilot_handbook/

Contents Chapter 1-Aircraft Structure Chapter 2-Principles of Flight Chapter 3-Aerodynamics of Flight Chapter 4-Flight Controls Chapter 5-Aircraft Systems Chapter 6-Flight Instruments Chapter 7-Flight Manuals and Other Documents Chapter 8-Weight and Balance Chapter 9-Aircraft Performance Chapter 10-Weather Theory Chapter 11-Weather Reports, Forecasts, and Charts Chapter 12-Airport Operations Chapter 13-Airspace Chapter 14-Navigation Chapter 15-Aeromedical Factors Chapter 16-Aeronautical Decision Making

The Airplane Flying Handbook (FAA-H-8083-3A) is the hands-on, how-to guide to flying all the maneuvers required for the private pilot and commercial pilot certificates. It is designed to assist student pilots learning to fly airplanes and to help current pilots and flight instructors expand their knowledge and skills. It's also one of the official references that pilot examiners use when testing the flying skills of pilots who are taking check rides.

This 210-page handbook is available for download in seven parts (Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, and Part 7) in PDF format.

http://www.faa.gov/library/manuals/aircraft/airplane_handbook/

Contents Chapter 1-Introduction to Flight Training Chapter 2-Preflight, Postflight, and Ground Operations Chapter 3-Takeoffs and Climbs Chapter 4-Basic Flight Maneuvers Chapter 5-Slow Flight, Stalls, and Spins Chapter 6-Ground Reference and Performance Maneuvers Chapter 7-Airport Traffic Patterns, Approaches, and Landings Chapter 8-Faulty Approaches and Landings Chapter 9-Flight by Reference to Instruments Chapter 10-Night Operations Chapter 11-Navigation Systems Chapter 12-Emergency Operations Chapter 13-Transition to Different Airplanes and Systems Chapter 14-Transition to a Multiengine Airplane Chapter 15-Transition to Tailwheel Airplanes Chapter 16-Transition to Seaplanes Chapter 17-Transition to Skiplanes Chapter 18-Aeronautical Decision Making

The Instrument Flying Handbook (FAA-H-8083-15) is the FAA's guide to all of the aeronautical knowledge and skills required to operate in instrument meteorological conditions (IMC). It is designed for pilots training for an instrument rating, and for the instrument flight instructors who teach them. The Instrument Flying Handbook includes both theory and practical guidance on how to operate an aircraft solely by reference to instruments, from filing a flight plan and working with ATC to maintaining straight-and-level flight, flying DME arcs and holding patterns, and shooting ILS approaches.

This 280-page handbook is available for download in two parts (Part 1 and Part 2) in PDF format.

http://www.faa.gov/library/manuals/aviation/instrument_flying_handbook/

Contents Chapter 1: Human Factors Chapter 2: Aerodynamic Factors Chapter 3: Flight Instruments Chapter 4: Airplane Attitude Instrument Flying Chapter 5: Airplane Basic Flight Maneuvers Chapter 6: Helicopter Attitude Instrument Flying Chapter 7: Navigation Systems Chapter 8: The National Airspace System Chapter 9: The Air Traffic Control System Chapter 10: IFR Flight Chapter 11: Emergency Operations Appendices Glossary Index

The Instrument Procedures Handbook, a guide for advanced instrument pilots published by the FAA, is available for free download at:

http://www.faa.gov/library/manuals/aviation/instrument_procedures_handbook/

The Aeronautical Chart User's Guide

To learn more about aviation charts, you can download the Aeronautical Chart User's Guide (available in several parts in PDF format) from the FAA's National Aviation Charting Office (NACO): http://www.naco.faa.gov/index.asp?xml=naco/online/aero_guide

FAA regulations (FARs), the Aeronautical Information Manual, and many other references of interest to pilots, are available free online in both HTML and PDF format at http://www.faa.gov/atpubs/.

A wealth of practical information for pilots is also available free from the AOPA Air Safety Foundation's Online Safety Center at http://www.aopa.org/asf/. Resources include a variety publications in PDF format, free online courses, etc.

You can also find much free information about weather, avionics, and other subjects on the Web. For example, most manufacturers of GPS navigation gear offer their user manuals, PC-based simulators, training syllabi, and other resources via their Web sites. You needn't be an owner of the equipment to download the information and resources. See, for example, http://www.garmin.com/aviation/products.html#panel-mount.

Subpages
I broke this into subpages directly following the top-level headings that were already present. In some cases, I think this leaves chapters that have too narrow a scope, but it seemed better to have it split down so that people could work on it. If someone wants to join some of the chapters together (or restructure them entirely) feel free. --Fishpi (discuss • contribs) 22:31, 12 February 2011 (UTC)

Suggested Reordering
As was discussed, for the purpose of PPL training, there are a lot of free materials which are very good already available. Perhaps what there is not, however, are books that introduce potential pilots to the basics they need to feel brave enough to venture into a flying school.

Perhaps you might consider topics like this:

How do people become pilots What can you do with a PPL What do pilots learn Meet a plane (all the things you'll need to know to feel comfortable) Your First Lesson How to choose a flight school

Just an idea. Dwt2 (discuss • contribs) 03:17, 4 August 2016 (UTC)

Okay, I see now that there is another book very similar to that. https://en.wikibooks.org/wiki/Becoming_a_Private_Pilot/Getting_Your_Private_Pilot_License Perhaps a collaboration would be a good idea. Dwt2 (discuss • contribs) 03:18, 4 August 2016 (UTC)

title: Talk:Becoming a Private Pilot


text:
User talk:Moa3333

Wikisolutions
I'm not quite sure what this is all about. The title would tend to suggest it's a guide to solutions to wiki-related things. Is this supposed to be like a catalog of open-source software? Perhaps a better name might be in order?

Also we don't really like users using very short category names like Category:WS. Have a look at WB:NP. - Aya T C 22:33, 11 August 2005 (UTC)

 * Is not supposed to be a catalog, and not only about Open Source. For now it is like this because OS is what is intresting for me. ut someone else can come and write pages about Proprietary software or even not related to computers maybe. Also tips and links to web resources for programmers or for system administrators. It can contain anythink usefull for whoever want to contribute.
 * It is not good to call it catalog, list of, collection, database, etc because first of all there are already lists of on Wikipedia, and seccond, it means that everything is only a place to find mass-organised information that you still nead to process to find anything close to what you are searching for. A better way to call it should be solutions, guidance, guides, expert advice, advice, customised  or special information. Some time people search for a very precise thing, and it is better to have a page that describes exactly what options he has for his very personalised and particular probem. It is about customisation, giving people exactly want to allow this.hat he is searching for and what are the posibilities for exactly what he is searching. This is why many pages are only about open source because this is what i am intrested in. Someone else whout also be intrested in proprietary software or anything else.
 * A better name its ok. Maybe Wikiguidance is a good one, or Wikiadvice.
 * The category WS is mostly used to include other categories and is supposed to contain a limited number of pages. About the other categories, for example, WS/S:Name they can be changed into  Wikisolutions/Software:Name but this will make huge Categoty names and it is only for that reason i have used WS/S:Name.
 * A change of name and even more of how categories and pages are named, should be done by a script, because it is quite difficult to do it manualy. Also i think if the project should stay on Wikibooks. It is a little special for a book but i think Wikibooks is the best place to put it on wikimedia. Moa3333 15:56, 14 August 2005 (UTC)

 * This sounds like a completely new project, and as such, we do not allow the use of Wikibooks to develop new projects, especially ones with goals as vague as "It can contain anythink usefull for whoever want to contribute." People might consider it "useful" to contribute hardcore pornography, but we really don't w   roject is sufficiently different, they will grant you your own wiki on which to develop it. - Aya T C 16:37, 14 August 2005 (UTC)

 * See About for details of our project's goals. See also: Votes for deletion/Wikiversity for another example of a project that is in the process of being relocated. Note that Wikicities is a good place to start new projects, although they will only allow projects which are sufficiently dissimilar to ones they already host. This project you describle sounds somewhat similar to Wikianswers, but if you can convince the admins there that your project is sufficiently different, they will grant you your own wiki on which to develop it. - Aya T C 16:37, 14 August 2005 (UTC)

 * Ok, i agree the project should be relocated since this will alow better definitions of rules. I am not intrested "to contribute hardcore pornography" but if someone is intrested in this maybe it is better to have less restrictive rules to avoid one or more forks in the future.

 * Wikianswars is a good starting point, and it neads two rules: avoid to have two questions with the same answer(forks) and answers should be of two types: some that present the answer if it is simple and fully documented and unique. If the answer is not unique or simple then it should point to other web sites or wikis that try to give answers. In other words some answers cannot be given completly and should be redirected to more competent web sites. This type of answer is what wikisolutions was supposed to be.

 * I will think about how to make the relocation (even if i don't like google adds and would like to see wikianswers relocated to meta or a new mediawiki project). First only important rules should be kept, the other will be only sugestions on my personal page. Seccond, all depends on how people on wikianswers agree. If they do not agree to give complete answers or give external links if the answer is not unique then we nead two projects: one with simple "embeded" answers and the other with "links to external solutions/answers". (example: what are the free linux drivers for audio?  must be a question that use external links and not try list the drivers inside the answer, witch is impossible to be complete and up to date)

 * Relocation will take time. I will say on the main page that the project is relocating and all contributions should be done to wikianswers, but it may take time untill the merge is done. It should be nice and good to keep the pages in wikibooks until then with no new contributions. Moa3333 21:48, 17 August 2005 (UTC)

 * here is Wikianswers discussion page Moa3333 22:12, 17 August 2005 (UTC)

 * Hello Moa3333. I've replied at Wikianswers, which I don't think is the best location for this content. If you want to discuss this, my talk page at meta (if you want to keep this in Wikimedia), or my talk page at Wikicities (if you want a wiki there), would be best since i check those more often than I check Wikibooks or Wikianswers. Angela

 * Project migration finished. New project is caled the HowTo project.

Status of Wikisolutions
This is more of a followup. You had some discussions earlier with User:Aya about this project, and it is clear that the bulk of the project has been moved to Wikicities. I would like some confirmation on that, and to decide what to do with the content on Wikibooks. I could put this up for a VfD, but if you, the primary author for most of this content were to agree that it needs to be deleted, it will go. There is quite a bit of material there, and I just want to make sure you have everything you are looking for and want to copy out before it disappears. --Rob Horning 17:31, 5 February 2006 (UTC)

Usualy all the pages are in the ne WikiHowTo project on wikicities since September 2005 or so. They were also modified since then, so the pages here are now old. It is ok to delete all pages, excetping the main page with the redirect. Moa3333 21:32, 8 February 2006 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User talk:Moa3333


text:
Blender 3D: Noob to Pro/Glossary

A

 * Alpha Channel is an additional channel in a 2D image for transparency. In an image element which stores a color for each pixel, an additional value is stored in the alpha channel containing a value between 0 and 1. A value of 0 means that the pixel does not have any coverage information; i.e. there was no color contribution from any geometry because the geometry did not overlap this pixel. A value of 1 means that the pixel is fully opaque because the geometry completely overlapped the pixel.

 * Ambient Light is light that doesn't seem to come from a specific source, but is just there. Look under the desk - it's pretty dark, but there's some light there. In the real world, this is caused by stray photons bouncing around and occasionally ricocheting under the desk. Ambient light is the basic, minimal amount of light in the whole scene. Adding too much ambient light makes a scene look washed out. Since the light doesn't come from anywhere, all sides of an object are illuminated equally, and it won't have any shading on it.

 * Ambient Occlusion (AO) is a ratio of how much ambient light a surface point would be likely to receive. It simulates a huge dome light surrounding the entire scene. If a surface point is under a foot or table, it will end up much darker than the top of someone's head or the tabletop.

 * Armature is the interconnection of bones that form the skeleton of an animated figure. The Inverse Kinematics library contains the code to make armatures move. The armature must still be rigged with 3D objects to give shape to its head, hands, trunk, feet, etc.

B

 * Background image: a 2D image ("picture") that is placed "behind" the entire 3D scene, like a backdrop on a movie set. Blender permits the placement of these images in all six directions from the origin: back, front, top, bottom, left, right.
 * Bake: to precompute computationally-intensive elements of an animation. For example, in a physics simulation involving the behaviour of fluids or clothing, you would set up the physical parameters, then compute (bake) the positions and shapes of the objects over the duration of the animation. Afterwards, you can assign materials and lighting, and then render the frames to produce the actual animation. Doing the baking as a separate step, and saving the results from that, means you can change your mind about the materials and lighting and rerender the frames more quickly.
 * Bézier surfaces were first described in 1972 by the French engineer Pierre Bézier who used them to design automobile bodies. Bézier surfaces can be of any degree, but bicubic Bézier surfaces generally provide enough degrees of freedom for most applications.

 * BF is Blender Foundation

 * Blend - to Blend, working with Blender; also Blender's file extension.

 * Bounce Light: Simple lighting situations have a single light, called a key light, illuminating one side of an object. This creates strong shading and definition of the volume of the object. However, a 3D light will often make the contrast too great - the dark side of the object is completely black since no light is hitting it. In reality it would still be lit a little, just not as much as the brightly lit side, because of light bouncing around the room and hitting the dark side of the object. In realtime 3D, bounce light is not calculated, so you have to create it yourself. Either add a little ambient color, or put a second, less bright directional light pointing the opposite direction to give a little light to the shadows.

 * Bump mapping is a technique where at each pixel, a perturbation to the surface normal of the object being rendered is looked up in a texture map and applied before the illumination calculation is done. Bump Mapping use a gray-scale image map to change the direction of surface normals. You can use this to simulate height, so that you can paint wrinkles and bumps. 50 % grey means neutral (no change is made), lighter means higher, darker means lower. Note that the position of faces is not actually changed; by rotating just the normals, lighting will change too, to give the illusion of a height difference. This has downsides too: the outline of objects isn't changed, so the trick is given away. For similar effects you can use Displacement Mapping and Normal Mapping.

C

 * Caustics in optics is a bundle of light rays. For example a caustic effect may be seen when light refracts or reflects through some refractive or reflective material, to create a more focused, stronger light on the final location. Such amplification, especially of sunlight, can burn — hence the name. A common situation when caustics are visible is when some light points on glass. There is a shadow behind the glass, but also there is a stronger light spot. Nowadays, almost every advanced rendering system supports caustics. Some of them even support volumetric caustics. This is accomplished by raytracing the possible paths of the light beam through the glass, accounting for the refraction, reflection, etc.
 * CG is Computer Graphics
 * CGI is Computer Generated Imagery

D

 * Depth of Field (DOF) is the distance in front of and behind the subject which appears to be in focus. For any given lens setting, there is only one distance at which a subject is precisely in focus, but focus falls off gradually on either side of that distance, so there is a region in which the blurring is tolerable. This region is greater behind the point of focus than it is in front, as the angle of the light rays change more rapidly; they approach being parallel with increasing distance.

 * Diffuse Light is even, directed light coming off a surface. For most things, the diffuse light is the main lighting we see. Diffuse light comes from a specific direction or location, and creates shading. Surfaces facing towards the light source will be brighter, while surfaces facing away from the light source will be darker.

 * Directional Light is a light that has a specific direction, but no location. It seems to come from an infinitely far away source, like the sun. Surfaces facing the light are illuminated more than surfaces facing away, but their location doesn't matter. A Directional Light illuminates all objects in the scene, no matter where they are.

 * Displacement Mapping uses a greyscale heightmap, like Bump Mapping, but the image is used to physically move the vertices of the mesh at render time. This is of course only useful if the mesh has large amounts of vertices, but the (relatively) new "Simple Subdiv" subsurf option allows you to add more vertices at render time which will be moved by the displacement. This makes it much slower than Bump Mapping, as there need to be many more faces to render, but it is much more realistic.

E

 * Environment Maps (EnvMaps) is the method of calculating reflections. Involved rendering images at strategic positions and applying them as textures to the mirror. Now in most cases obsoleted by Raytracing, which though slower is easier to use and more accurate.

F

 * Focal Length of a lens is the distance along the optical axis from the lens to the focus (or focal point). The inverse of a lens' focal length is called its power.

 * Focus of a lens is the point onto which collimated light parallel to the axis is focused.

 * Foreshortening

 * Fresnel lens is a type of lens invented by Augustin-Jean Fresnel. Originally developed for lighthouses, the design enables the construction of lenses of large size and short focal length without the weight and volume of material which would be required in a lens of conventional design. As it relates to rendering, fresnel refers to the tendency of materials to be more reflective when light strikes at a high angle of incidence-- think of how sunlight reflects from distant water, but penetrates closer water, or of how road glare is most extreme at dawn or dusk.  This varies with material, and specification of fresnel is an important part of material definition.

G

 * GE is Game Engine.

 * Global Illumination (GI) is a superset of radiosity and ray tracing. The goal is to compute all possible light interactions in a given scene, and thus obtain a truly photorealistic image. All combinations of diffuse and specular reflections and transmissions must be accounted for. Effects such as colour bleeding and caustics must be included in a global illumination simulation.

 * Gouraud shading is a method used in computer graphics to simulate the differing effects of light and colour across the surface of an object. In practice, Gouraud shading is used to achieve smooth lighting on low-polygon surfaces without the heavy computational requirements of calculating lighting for each pixel. The technique was first presented by Henri Gouraud in 1971.

H

 * High Dynamic Range Image (HDRI) is a set of techniques that allow a far greater dynamic range of exposures than normal digital imaging techniques. The intention is to accurately represent the wide range of intensity levels found in real scenes, ranging from direct sunlight to the deepest shadows. The use of high dynamic range imaging in computer graphics has been popularised by the work of Paul Debevec. Blender uses Yafray for these techniques.

I

 * Index Of Refraction (IOR) is about the way that light passes through different types of materials... diamond, glass, water etc. When a light ray travels through the same volume it follows a straight path. However if it passes from one transparent volume to another, it bends. This is why a straw in water looks bent. The amount of bending differs between materials. The angle by which the ray is bent can be determined by knowing two things: the angle at which the incoming ray has been cast and the Index of Refraction. This IOR value is unique for every material. Glass has an IOR of about 1.5 and water 1.3. By increasing the IOR value for a Blender material, you can control how much the environment behind the transparent object is distorted, and thus improving the realism of the shader.

 * Interpolation (IPO) is an animation curve: it indicates how the object must "move" between an initial and a final position, at the rate determined by the rendering engine. Objects can be animated in many ways. They can be animated as Objects, changing their position, orientation or size in time; they can be animated by deforming them; that is animating their vertices or control points; or they can be animated via very complex and flexible interaction with a special kind of object: the Armature.

 * Inverse Kinematics (IK) is the process of determining the movement of interconnected segments of a body or model, starting from the desired motion of the endpoints of the armature. Using ordinary Kinematics on a hierarchically structured object you can for example move the shoulder of a puppet. The upper and lower arm and hand will automatically follow that movement. IK will allow you to move the hand and let the lower and upper arm go along with the movement. Without IK the hand would come off the model and would move independently in space. The Blender Armature System includes Inverse Kinematics. For general armatures there are many possible solutions to the IK.

J

 * JPEG Acronym for Joint Photographic Expert Group (pronounced jay-peg) is a commonly used standard method of lossy compression for photographic images. The file format which employs this compression is commonly also called JPEG; the most common file extensions for this format are .jpeg, .jfif, .jpg, .JPG, or .JPE although .jpg is the most common on all platforms.

K

 * Keyframe is a frame in an animated sequence of frames that was drawn or otherwise constructed directly by the user. When all frames were drawn by animators, the senior artist would draw these frames, leaving the "in between" frames to an apprentice. Now, the animator creates only the first and last frames of a simple sequence; the computer fills in the gap. This is called tweening.

L

 * Luminosity (more properly called luminance) is the density of luminous intensity in a given direction. In astronomy, luminosity is the amount of energy a body radiates per unit time. It is typically expressed in the SI units watts, in the cgs units ergs per second, or in terms of solar luminosities, Ls; that is, how many times more energy the object radiates than the Sun, whose luminosity is 3.827×1026 W.

M

 * Motion Blur is the simulation of the phenomenon that occurs when we perceive a rapidly moving object. The object appears to be blurred because of our persistence of vision. Doing motion blur makes computer animation appear more realistic. It can be thought of as adding back some of the time dependence expressed in the Rendering Equation.

N
s0= texture(x, y, z) s1= texture(x+nabla, y, z) s2= texture(x, y+nabla, z) s3= texture(x, y, z+nabla)
 * Nabla. Ton wrote: Almost all procedural textures in Blender use derivatives for calculating normals for texture mapping (with as exception "Blend" and "Magic). The texture normal, the derivative, is calculated by using four samples in the texture formula:

normal[0]= s0-s1 normal[1]= s0-s2 normal[2]= s0-s3

Up to now, the "nabla" offset was a constant (0.025) which worked fine in most cases, but doesn't give proper control over the way a texture is sampled, for example to make the effect smoother or sharper. This feature especially is useful in combination with the ColorBand feature.

 * Non-Linear Animation (NLA) allows the animator to edit motions as a whole, not just the individual keys. Nonlinear animation is not just about editing and manipulating groups of keyframes, but it also allows you to combine, mix, and blend motions to create entirely new animations.

 * Nonuniform Rational B-Splines (NURBS) is a computer graphics technique for generating and representing curves and surfaces.

 * Normal (Surface Normal) to a flat surface is a three-dimensional vector which is perpendicular to that surface. A normal to a non-flat surface at a point p on the surface is a vector which is perpendicular to the tangent plane to that surface at p.

 * Normal Mapping is similar to Bump Mapping, but instead of the image being a greyscale heightmap, the colours define in which direction the normal should be shifted, the 3 colour channels being mapped to the 3 directions X, Y and Z. This allows more detail and control over the effect.

O

 * Orange is the first Blender open movie project.

 * Oversampling (OSA), also called Anti-Aliasing is the technique of minimizing aliasing when representing a high-resolution signal at a lower resolution. In most cases, anti-aliasing means removing data at too high a frequency to represent. When such data is left in a signal, it causes unpredictable artifacts.

P

 * Phong shading term is used indiscriminately to describe both an illumination model and an interpolation method in 3D computer graphics. Phong reflection is a local illumination model and can produce a certain degree of realism in three-dimensional objects by combining three elements - diffuse, specular and ambient for each considered point on a surface. It has several assumptions - all lights are points, only surface geometry is considered, only local modelling of diffuse and specular, specular colour is the same as light colour, ambient is a global constant.

 * Point Light is a light that has a specific location and radiates equally out in all directions. Examples of point lights would be candles or bare lightbulbs. Surfaces close to the point light are brighter than those which are far away. Point lights have attenuation, which controls how quickly the light intensity drops off as you move away from it. Lights with high attenuation are very localized, while lights with low attenuation will spread farther.

 * Polygonization (of meta-surfaces) is the process of approximating the meta-surface via polygons so it can be displayed/rendered in Blender.

 * Purple runs as a normal Verse client. It implements a node database to mirror the contents of its host. It loads the plug-ins, which reside in libraries, from local disk as DLLs or shared objects depending on the platform.

Q

 * Quaternion is a representation of 3D rotations with four numbers. It can be interpreted as an extension of complex numbers to 3D. The interpretation of the four numbers is not very intuitive for a human, but the numerical advantage of quaternions is that it is the smallest mathematical representation that does not suffer from the gimbal lock singularity problem. This problem occurs for example with Euler angle representations, when a small change in the 3D orientation can give rise to a large change in Euler angles.

R

 * Radiosity is a more accurate but also more process-intensive technique than raytracing, that calculates patterns of light and shadow for rendering graphics images from three-dimensional models. One of the many different tools which can simulate diffuse lighting in Blender.

 * Raytracing works by tracing the path taken by a ray of light through the scene, and calculating reflection, refraction, or absorption of the ray whenever it intersects an object in the world. More accurate than Scanline, but much slower.

 * Render: to generate actual viewable images from a 3D model or scene. This may or may not need to happen in real time; for example an interactive game requires real-time rendering, whereas a feature film does not. These situations require very different rendering techniques.

 * Refraction in geometric optics is the change in direction of a wave due to a change in velocity. It happens when waves travel from a medium with a given refractive index to a medium with another. At the boundary between the media the wave changes direction; its wavelength increases or decreases but frequency remains constant. For example, a light ray will refract as it enters and leaves glass.

 * Relative Vertex Keys (RVK) are part of a keyframe animation system that operates on vertex level objects. Each (shape) key is stored as a morph target such that several keys may be blended together to achieve complex mesh animation. With RVK you can create facial expressions, speech, and other detailed animated keyframed movements within your mesh-based models.

 * Rig: the controls that aid in the manipulation of a digital character.

 * Rigging is the process by which a person creates constraints and relationships between objects that will generate controls to aid in the manipulation of a digital character.

S

 * Scanline is one row of pixels in the final render. Also the term for one of the methods of rendering which Blender can use. It is much faster than Raytracing, but allows fewer effects, such as reflections, refractions, motion blur and focal blur.

 * Seed: a starting number for generating a random-looking number sequence. Using the same seed will always give you the same sequence. Technically, such a sequence is not truly random, it is only pseudorandom.

 * Shader: an algorithm for computing the appearance of a given material based on the colour, angle and intensity of the light. Specular shaders produce a more shiny, mirrorlike finish, while diffuse shaders give a duller surface appearance. There are also toon shaders, which are deliberately designed to produce an effect more akin to a cartoon drawing, with delineated object borders and less gradation of colours over a surface.

 * Shadows: simulated lights don't normally cast shadows. And, they also pass through solid objects - so a light inside a closed box would actually illuminate things outside the box as if the box were transparent. The shading on objects is only calculated based on the angle of the surface.

 * Specular Light refers to the highlights on reflective objects, like diamonds, billiard balls, and eyes. Specular highlights often appear as bright spots on a surface, at a point where the light source hits it directly. Ambient, Diffuse, and Specular are called the three components of a light source. Each one is given a color, which, when added together, create the final color of a light. For most lights, the main overall color of the light is defined by the Diffuse color. Sunlight or lightbulbs would be white, while moonlight would be a darker blue, and a candle would be yellow. You can use the ambient color to adjust the overall color range of the light source; or, you can get a slight tint to shadows by making the diffuse component yellow and the ambient a slight blue. In many lights, the ambient color is left at black, meaning that it won't have any effect. Specular components are often left at white, but you can make them different colors to get interesting effects. Most of the time you can completely ignore the specular and diffuse settings on a light, but just be aware that the way you set the color is by specifically setting the diffuse color. The final color that an object appears to be is a combination of the light hitting it and the color of the surface.

 * Spotlight is a light with both location and direction. A spotlight sends out a cone of light defined by the spotlight angle, and illuminates only objects within that cone. Spotlights also have attenuation, as well as a parameter that controls whether the spot of light is sharply defined or has smooth edges. These 4 types of lights are listed in order of computational complexity; the more lights you have, the more work the computer has to do. Generally it's a good idea to use directional lights whenever possible, since they're the cheapest, and use pointlights and spotlights sparingly.

 * Stucci is one of the classes of blender textures. Stucci is not an English word, but is used in Blender as the plural of stucco.

 * Subdivision Surface (Subsurf) is the tool which subdivides your model at render-time, without affecting your mesh at design-time. There are two subsurf algorithms in Blender to choose from - Simple Subdiv, which doesn't affect the shape of your mesh, and is used to add detail to displacement mapping or render-time radiosity, both of which operate on a per-vertex basis. The other is Catmull-Clark, a common subdivision algorithm which smooths out curves, and allows you to make complicated smooth surfaces (e.g. people, plants, etc.) with very few faces. However this algorithm can sometimes (read: often) have strange results with meshes containing triangles or vertices with many edges ("poles"), unless it is correctly handled.

 * Sub Surface Scattering (SSS) is a mechanism of light transport in which light penetrates the surface of a translucent object, is scattered by interacting with the material, and exits the surface at a different point. All non-metallic materials are translucent to some degree. In particular, materials such as marble, skin, and milk are extremely difficult to simulate realistically without taking subsurface scattering into account.

T

 * Tuhopuu is an experimental version of Blender that is like a code playground, developers can put their new code in there to be tested and played with by users before it gets put into the official Blender. Tuhopuu is Finnish for "Tree of destruction".

 * Tweening is short for in-betweening, the process of generating intermediate frames between two images to give the appearance that the first image evolves smoothly into the second image. Tweening is a key process in all types of animation, including computer animation. Sophisticated animation software enables one to identify specific objects in an image and define how they should move and change during the tweening process. Another word for tweening is interpolation.

U

 * UV Mapping (UV) This refers to the process of re-parameterizing a 3d object with dimensions x, y and z into a 2d plane with coordinates u and v. Most texturing requires this step because it tells the program HOW to apply a 2d image map onto a 3d object.  If all your textures must be 2d and flat, the easiest way to determine what pixel goes where is if your model is flattened and made 2d.  It also establishes a relationship between a 2d image and the mesh such that if the mesh deforms, the image map will deform along with it.  Think of it as skinning a cat and pinning its hide onto cardboard to facilitate painting it!

V

 * Verse is a network protocol that lets multiple applications act together as one large application by sharing data over a network. If one application makes a change to shared data, the change is distributed instantly to all the other interested clients.

W

 * WC is Weekend Challenge.

 * WIP is Work In Progress.

Y

 * Yet Another Free Raytracer (YafRay) is an open source ray tracing program that uses an XML scene description language. It has been integrated into, and is often used to render scenes made in, Blender.

title: Blender 3D: Noob to Pro/Glossary


text:
Wikijunior:Solar System/Saturn/Dione

Dione is a moon of the planet Saturn. It was first photographed in some detail when the Voyager 1 mission passed by Saturn in 1980. The Cassini spacecraft started taking more closeup pictures in 2004, and we now know much more about this moon.

How big is Dione?
Dione is 1118 km across. This is much smaller than our Moon, which is almost 3,500 km across. It is one-fifth as large as Titan, the largest moon in orbit around Saturn.

What is its surface like?
This is a cold, icy world with a thin layer of oxygen for its atmosphere. The side of the moon that faces toward the direction of its orbit is covered from craters that were made by collisions with asteroids. On the back side are bright, wispy streaks across the surface. These are cliffs in the ice that were caused when the surface shifted about.

How long is a day on Dione?
It takes 2.74 days to complete an orbit around Saturn. This is just under 2 days and 18 hours. It also takes the same amount of time for the moon to rotate around the axis. This means that the same side of Dione is always facing toward Saturn, in much the same was as our Moon always keeps the same face toward us.

What is it made of?
Dione has a covering of ice surrounding a rocky interior. It has a higher portion of rock inside than any other moon of Saturn except Titan.

How much would Dione's gravity pull on me?
A person standing on the surface would weigh less than one-thirtieth as much as they would on Earth.

Who is it named after?
This moon is named for one of the titans from Greek mythology. She was an addition to the original twelve titans mentioned by the Greek poet Hesiod.

How was it discovered?
It was discovered by the Italian astronomer Giovanni Cassini in the year 1684. At the time he was the director of the Paris Observatory in France.

Wikijunior Sonnensystem/ Saturn/ Dione

title: Wikijunior:Solar System/Saturn/Dione


text:
Talk:D'ni

Tweaking
Domahreh from the DLF here, corrected some mistakes here and there, nothing too gigantic... might want to switch over to the official Cyan font at some point, since the other doesn't seem to be working properly...
 * Thanks!! This wikibook exists for some time, however it had no serious contribution before :)

title: Talk:D'ni


text:
User:Ppragman

Hi my name is Pat, and I'm a Private Pilot working on other ratings. I speak Russian, and am interested in Wiki because of the type of communication it facilitates between people. Quite interesting to me.

title: User:Ppragman


text:
User talk:Glitch010101~enwikibooks

Ardvark the Aardvark now on Novelas
Ardvark the Aardvark's new home is wikicities:c:novelas:Ardvark the Aardvark. Boy he gets around! :) GarrettTalk 23:51, 11 August 2005 (UTC)
 * Thanks for the transwiki and all the healthy discussion around this! I'm glad to see that wikicities is here for projects like this, and I think the debate was a good one to have. The "no fictional material that's not educational" paradox needed to be cleared up. Glitch010101 01:24, 12 August 2005 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Glitch010101. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Glitch010101~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:14, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:00, 19 April 2015 (UTC)

title: User talk:Glitch010101~enwikibooks


text:
Muggles' Guide to Harry Potter/Magic/Wand

Overview
The primary method of performing magic in the Harry Potter series requires the use of a magic wand. The wand serves to focus and amplify the magical energy present in the witch or wizard.

Extended Description
Wands are typically made of wood with a core of some magical material; we hear of wands made with Phoenix tail feathers, Unicorn hair, Dragon heartstrings, and Veela hair, but it is likely that there are many other possible materials that can be used. When a witch or wizard goes to buy a wand, they must try out different combinations of woods, cores, and lengths until they find a wand that works for them. One thing which is told to us repeatedly is that "the wand chooses the wizard"; that a particular combination of wood and magical core, with other details of their manufacture, make a particular wand ideal for a particular wizard, and that it is difficult, if not impossible, to predict what sort of wand an individual wizard will be best able to use. It has been suggested that the length of the wand depends to some extent on the person's height (as Hagrid's wand is the longest one we hear of), the wood depends on the person's astrological signs and personality, while the core of the wand also reflects the user's personality. Of course, for any such suggestion, we can likely find counter-examples. We are told at the outset that it is very difficult to use someone else's wand; and Harry finds out in person, in  Harry Potter and the Deathly Hallows, that this is true.

It is possible to do some magic without the aid of a wand, but that magic is usually spontaneous and found only in untrained children. This is how Harry regrew his hair after the Dursleys cut it off, how he ended up on the roof of the school when Dudley and his gang were chasing him, and how he released the python in the zoo. It is suspected that accidental magic appears in moments of great stress or emotion.

Very few spells are shown that can be performed in a controlled manner without a wand. These include the Animagus transformation and Floo transport. (Note that while this last does not require a wand, it does require other equipment, notably Floo Powder.) It is uncertain whether Apparition and Disapparition require the use of a wand, as no wand gestures are indicated; we never see any wizards or witches apparating themselves without a wand. (Side-along apparition, as when Hermione carries Harry, with his broken wand, does not count, as Harry is not then Apparating, but rather riding on someone else's spell.) House-elves, among others, do not have wands and yet can apparate, however, their magic has been shown to be of a different class than human magic.

Analysis
There seem to be a very limited number of wizards who can actually produce wands, and they all have their own preferred ingredients and techniques. The only working wandmaker we are directly introduced to is Mr. Ollivander, who is the proprietor of a wand shop in Diagon Alley. Mr. Ollivander uses only three types of magical core for his wands: phoenix tail feathers, unicorn hair, and dragon heartstrings. Other wandmakers use other materials; for instance, Fleur Delacour's wand is made with the hair of a Veela as the core, a material Ollivander does not use as he finds it makes for a temperamental wand. Ollivander immediately identifies the wand used by Viktor Krum as a "Gregorovitch creation"; while he does not much care for the style, he does seem to think that it is a good enough wand. His ready identification and his discussion of the wand style indicates that he is very familiar with the style of this other wandmaker, if not with him personally; this also would indicate that we are looking at a restricted community.

Wands are made from nearly every tree type, and the author has chosen the wood for each character's wand based on its symbolic connotation. Harry's wand, for instance, is holly, which is believed to repel evil. Holly also represents protection, joy, happiness, masculinity, and overcoming anger. Christians also believe that the holy cross was made from holly. The word holly is derived from "holy". Viktor Krum's wand is hornbeam, a wood that represents strength, stubbornness, passion, moral fibre, ethics, and loyalty. It is also associated with a person who is considered the "salt of the earth" or a "common man". Rosewood, which is what Fleur Delacour's wand is made from, represents inner beauty, kindness, and gratitude, while Cedric's ash wand symbolizes adaptability, prudence, modesty, sacrifice, and sensitivity.

Wood alone does not empower a wand. Presumably, its core material magically fuses with the wood it is embedded into, activating the wand's power. It also seems to become somewhat sentient, allowing it to bond to a Wizard who shares similar qualities. Magical creatures provide the core material; Mr. Ollivander's wands only contain Unicorn hair, Phoenix feather, or Dragon heartstring, though other wandmakers use additional substances. Harry's wand contains a Phoenix feather. A Phoenix is a mythical bird that continually dies by bursting into flames and is then reborn from its own ashes, an act symbolizing resurrection and purity. Krum's wand contains Dragon heartstring, and though a Dragon is often associated with evil and destruction, in many cultures it represents qualities such as strength, wisdom, purification, renewal, and power. The Unicorn hair in Cedric's wand represents purity, innocence, loyalty, and mankind's dual nature (evil and goodness). Fleur's wand confirms Ron's suspicions that she is part Veela. The hair forming its core belonged to her Veela grandmother, making Fleur one-quarter Veela. This wand's core is apparently unusual; it seems to surprise Mr. Ollivander when he finds it, and may reflect the Veelas' more temperamental and volatile natures. As seen earlier in this book, the Veelas' real appearance is far different than the images they can project. Though Fleur is certainly beautiful and alluring, we don't know much about her inner character; at the time we discover the core material of her wand, about the only exposure we have to her is her supercilious air when being forced to accept the "little boy" Harry as a competitor in the Triwizard Tournament. The Veela hair may also represent transformation, adaptability, and even deception and seduction. Being that the hair belongs to someone closely related to Fleur, it may also symbolize the power of family, generational legacy, unity, and loyalty.

Ron's and Hermione's wands should also be noted. Hermione's is made from vine and contains Dragon heartstring. Vine can represent great bounty, renewal, and also extreme emotions such as joy and anger. Ron's first wand, his brother Charlie's hand-me-down, was ash and Unicorn hair. His second wand, the one that presumably "chose" him, is willow and Unicorn hair. Willow is associated with gaining knowledge, personal growth, healing, and repulsing evil. It can also represent death and mourning. Though wands typically perform less efficiently for someone who was not "chosen" or had not captured it from another Wizard, presumably a wand handed down within a family offers its allegiance to a close blood relative, in this case, Ron.

A wizard will generally have a single wand for an extended period of time, largely because it works well for him; and because a wizard is by and large powerless without his wand, he will protect it. This will allow wands to be used as a form of identification. We see a wand being used for identification in Harry Potter and the Deathly Hallows, where the disguised Hermione uses Bellatrix Lestrange's captured wand to prove her identity to a Gringotts goblin.

A little known fact unrelated to the series' plot is that the woods used in Harry's, Hermione's, and Ron's wands happen to correspond to some variants of the Celtic Tree Calendar, which is divided into thirteen lunar-based periods. Each one is represented by a different wood. The author has indicated that quite by accident she had selected an appropriate wood for Harry's wand from this calendar; Harry, being born on July 31, receives a wand made of holly wood. Similarly, she selected hawthorn wood for Draco Malfoy's wand without realizing that it was correct for his birthday. She does say that not all wands are selected according to the Celtic chart; Hagrid's wand, for instance, by his birthdate ought to be elder, but how could Hagrid have a wand that was anything other than oak? And while the Celtic assignment would suggest birch for Voldemort's wand, there are reasons for making it out of yew. To quote the author: "It was not an arbitrary decision: holly has certain connotations that were perfect for Harry, particularly when contrasted with the traditional associations of yew, from which Voldemort’s wand is made. European tradition has it that the holly tree (the name comes from ‘holy’) repels evil, while yew, which can achieve astonishing longevity (there are British yew trees over two thousand years old), can symbolize both death and resurrection; the sap is also poisonous." Ron's March 1 birthday falls within February 18 - March 17, which is ash. His new willow wand is outside this period, however. Hermione's vine wand reflects her September 19 birth date, which is within the Calendar's September 2 - September 29 cycle.

As we learned in Book 1, Voldemort's wand is yew and contains a tail feather from the same Phoenix that donated the one in Harry's wand. In European cultures, yew wood, which is toxic, is generally associated with long life, death and resurrection, transformation, as well as evil; this certainly seems to fit Voldemort. This wood being combined with a Phoenix feather core is curious, however. While a Phoenix can represent resurrection, its fiery demise also symbolizes purification. This hardly seems to apply to Voldemort, who, if he is resurrected, will probably be as evil, if not more so, as when he died. It is curious why Mr. Ollivander would craft a wand from wood having such a dark connotation, though its particular magical properties would naturally be a consideration.

Greater Picture
Dumbledore's wand, known as the Elder Wand, should also be mentioned. It is made from elder, a wood believed to intermingle both good and evil and whose flowers, which produce a strong odor, suggest death. The author has stated that a Thestral hair lies within the Elder Wand's core. Thestrals, gentle magical creatures often associated with death, appear first in Harry Potter and the Order of the Phoenix. A wand containing a such a hair can only be mastered by a witch or wizard who is unafraid of death.

The fact that "the wand chooses the wizard," introduced in the first book, becomes an important plot point in the seventh book of the series. Voldemort, convinced that Harry's ability to avoid him is due only to his wand with its core that is twin to Voldemort's own, seeks a wand more powerful than Harry's. He searches for the fabled Deathstick or Elder Wand, a wand that is unbeatable in a duel. This wand has left a long and bloody trail through history, and Voldemort in the end tracks it to its last rumoured owners: the wand-maker Gregorovitch claimed to have it, but it was stolen from him by Gellert Grindelwald, who in turn lost it to Dumbledore. Voldemort claims it from Dumbledore's tomb, but finding that it resists his commands, and believing that the wand will only transfer its allegiance when its previous owner is killed, murders Severus Snape, who had killed Dumbledore.

Mr. Ollivander tells Harry that death is not required to change a wand's allegiance, even the Elder Wand. Instead, merely forcefully removing it from its owner, either by physically wresting it from his hand or using a disarmament charm, can cause a wand to change "loyalty". (Presumably this only holds if the original owner does not reclaim his wand; else nearly every magical duel would end up with the loser left effectively wandless.) As a result, it being Draco Malfoy who had disarmed Dumbledore, the Elder Wand would owe allegiance to Draco. As Harry had captured Draco's regular wand, the one with which he had disarmed Dumbledore, the Elder Wand might transfer its allegiance to Harry; if not, according to what Ollivander tells Harry, it would still be Draco's wand, rather than Voldemort's. Thus Voldemort would be unable to receive its full benefit. As it turns out, the Elder Wand, apparently aware that Harry was holding the wand that had wrested it from its former owner, apparently had given its allegiance to Harry, and would avoid harming him.

While there is much talk in the seventh book about allegiances and awareness by the wands, it is never meant to be an indication that wands are alive. Like Muggle computers, the fact that a wand behaves in a particular manner may make it seem alive, but it remains inanimate and unthinking. A good indication of this is the way the Elder Wand shows allegiance to Harry; after all, it was not Harry who disarmed Dumbledore, but Draco. However, Harry is now carrying Draco's wand, which had itself transferred its allegiance to Harry when he wrested it from Draco. So the Elder Wand, rather than a specific person, apparently senses the holder of the wand that performed the successful charm as the one to whom it owes allegiance.

We note that in Harry Potter and the Prisoner of Azkaban, the Daily Prophet says that the "Muggles have been told that Black is carrying a gun (a kind of metal wand which Muggles use to kill each other)". Wands do indeed take much of the role that pistols (and other weapons) take in non-magical stories; this includes the concept of specially powerful weapons, weapons particularly suited for use by specific persons.


text:
Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bb5

3. Bb5 - Spanish Game
The essential move marking the Spanish Game, or Ruy Lopez. "It is the double king's pawn opening most commonly used in master play; it has been adopted by almost all players at some point in their careers and many play it from both the White and Black sides."

White threatens to trade off Black's c6-knight, leaving the e5-pawn undefended. It's not an immediate threat, because after 4. Bxc6 dxc6 5. Nxe5, Black can win the pawn back with 5... Qd4 or 5... Qg5.

Black can respond in a variety of ways. The most common move is the Morphy Defence 3... a6. This forces White to make a decision about the Bishop - retreat or exchange.

Many other moves are available, some neglecting completely the protection of the knight and the pawn and continuing development.

The opening is named after the 16th century Spanish priest Ruy López de Segura. The popular continuation is: 3... a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. c3 d5 9. exd5 Nxd5 10. Nxe5 Nxe5 11. Rxe5 c6 12. d4 Bd6 13. Re1 Qh4 14. g3 Qh3.

Theory table

 * 1. e4 e5 2. Nf3 Nc6 3. Bb5


text:
Chess Opening Theory/1. e4/1...c5

Sicilian Defence
The moves '''1. e4 c5''' constitute the Sicilian Defence, a counter-attacking opening in which players typically attack on opposite sides of the board. The Sicilian was introduced to the chess world in 1594 by Giulio Cesare Polerio and emerged into the mainstream in the early 20th century as a somewhat tame variation. With the discovery of new attacking ideas, it became Black's most feared weapon by the 1950s and is, pound for pound, the most exhaustively analysed of all openings.

Black's move 1...c5 seeks to create a half-open c-file, controls the important d4 square, and allows the black queen to venture out if desired, while the c-pawn itself is safe from attack, unlike the e-pawn after 1. e4 e5.

White's responses
1...c5 introduces an element of asymmetry into the position; if White were to respond with 2. c4 (the English-like Staunton–Cochrane variation) imitating Black's move, that would weaken the d4 square and make it more difficult to play d4 later on.

Faced with a pawn on c5, White may choose to play 2. d4 (Smith–Morra Gambit) anyway which typically leads to a pawn sacrifice for quick development. After 2...cxd4, White can play 3. c3, sacrificing another pawn in order to play 4. Nxc3 to gain an advance in development in the Morra Gambit.

A more common idea is for White to postpone d4 for a move while they increase their own control of the square. This can be achieved by either 2. Nf3 typically leading to the main lines of the Sicilian (Open Sicilian) or by 2. c3 attempting to establish a strong pawn centre.

Much less common is the attempt to undermine the c-pawn's control of d4 by playing 2. b4 (Wing Gambit) to tempt it off-centre. Since it is considered safe for Black to take the offered pawn and hold on to it, a more recent idea has been to prepare b4 with 2. a3 (Mengarini variation).

White may postpone the fight for d4, typically with 2. Nc3 (Closed Sicilian) though 2. f4 (Grand Prix Attack) is also played. 2. f4 is a violent attacking move, 2. Nc3 typically leads to a more closed and slow-burning position, although f4 frequently appears later.

Statistics
Databases give White approximately 36% winning chances, drawing is at 30%, and Black wins 33%.

Estimated next move popularity: Nf3 74%, Nc3 10%, c3 7%, d4 3%, Bc4 2%, f4 2%, d3 1%, b3 1%, c4 1%, Ne2 1%, g3 0.4%, b4 0.4%, other moves less than 0.3%.

Note that these move frequencies are biased toward databases of stronger players. The next move frequency may be very different for club players. For instance, see the data from the Lichess database below where 2. Nf3 occurs less commonly at only 56% of the time while 2. Bc4 occurs as often as 7% of the time.

Theory table
1. e4 c5

title: Chess Opening Theory/1. e4/1...c5


text:
Introduction to Game Theory/Prisoner's Dilemma

Let's start by jumping right in and looking at a game. The game commonly referred to as The Prisoner's Dilemma is a classic example used to demonstrate game theory. It is usually explained through the use of this story, although the actual game called The Prisoner's Dilemma - often just called PD for short, is not limited to this situation. The underlying dynamics of it can be used to describe all sorts of phenomena.

The Story
Two men, Andy and Bob, were arrested after an armed robbery. The police had enough evidence to convict the two for the theft of the get-away car, but not enough to convict them for the actual armed robbery. However, if the police could get a confession from either of the two men they could conceivably convict them both for the armed robbery.

The police locked the two men in two separate rooms and gave them each the same offer:

 * If Andy confessed and Bob stayed silent, then Andy would go scot-free and Bob would be charged for the robbery and get 10 years in jail. Of course, this worked the other way around as well. If Bob confessed and Andy stayed silent, Andy would receive the 10 years.

 * If Andy confessed and Bob confessed as well, then they would both receive 7 years in jail.

 * If both Andy and Bob stayed silent, then they would both receive 2 years in prison for the get-away car robbery.

The two prisoners are left to make their decision without any way to contact each other. The question is: what did each person choose?

Solution
The solution that occurs every time this game is played (assuming each acts in his own best interests) is that both Andy and Bob will choose to confess, resulting in a sentence of 7 years each. This answer seems to be counter-intuitive, doesn't it? Why would both players choose to confess, an option that is clearly inferior to both of them staying silent and getting 2 years each? Not only this, but in terms of total years in prison, this is the worst possible outcome!

Explanation
The reason that both players choose to confess is easy to explain. Let's talk about Person A (and whatever holds for Andy, will hold for Bob as well because they are both in identical situations).

The following is the explanation assuming that Andy & Bob cannot communicate their choices to each other directly or indirectly.

Andy has the following Matrix:

'''If he confesses: '''

Minimum Jail Term: 0 Years (If Bob remains silent)

Maximum Jail Term: 7 Years (If Bob confesses)

'''If he remains silent: '''

Minimum Jail Term: 2 Years (If Bob remains silent)

Maximum Jail Term: 10 Years (If Bob confesses)

The expected payoff for the game (the average amount of benefit that a strategy will provide) is better — in this case, 3.5 years expected jail time for confessing versus 6 years for silence — if Andy confesses. Therefore, from a rational perspective, Andy should choose to confess rather than remain silent.

Also, it doesn't matter what Bob does - Andy is always better off confessing. If Bob confesses, Andy can get either 7 years for confessing or 10 for silence, and if Bob is silent, Andy can get either 0 years for confessing or 2 for silence. Unfortunately for Person Andy, this also holds true for Person Bob - who is always better off confessing. This means that if both agents do what is in their best interests, they will be 7 years together in prison! This demonstrates that in many games the "best" solution - the one where the total utility of the outcome is highest - is not the one which will ultimately occur.


text:
Chess Opening Theory/1. e4/1...d6

= Pirc Defense =

1...d6
The Pirc Defense is a modern opening and a response to white’s 1.e4. Black gives up the center and refuses to fill it with pawns but instead builds up slowly with defensive moves such as d6 (played now) and g6 (played in the near future) to fianchetto the DSB. White also often plays f4 and eventually e5 to add more control to the center. The Pirc Defense is an uncommon opening nowadays, but is very solid.

If White dislikes this opening, White can play /2. Nf3/ in order to transpose into the Sicilian Defense (2...c5) or into the Philidor Defense (2...e5).

If White agrees to play this defense, White has no reason not to build its pawn center with /2. d4/.

Theory table
1. e4 d6

title: Chess Opening Theory/1. e4/1...d6


text:
Chess Opening Theory/1. e4/1...d6/2. Nf3

= Pirc Defence = Black must now choose between going on in a modern defence with /2...g6/ or transposing into another defence with /2...c5/ or /2...e5/.

Theory table
.

1.e4 d6 2.Nf3


text:
Chess Opening Theory/1. e4/1...c5/2. Nf3

= Open Sicilian =

2. Nf3
White's move '''2. Nf3''' increased their control of the d4 square, enabling them to play d4 next move. Black cannot hope to resist White's plan any further, and should go about their own development.

/2...d6/ is the most popular move, controlling e5 for a potential advance of the e-pawn and letting the queen's bishop out, while also holding down the c-pawn should White go down a different path.

/2...e6/ is an older, though still popular move freeing the king's bishop, although d6 will often follow soon.

/2...Nc6/ is the most traditional move, and still played often today. It reserves options in the centre and keeps an eye on d4, as does /2...g6/   (the Hyper-Accelerated Dragon) with ...Bg7 to follow, and /2...a6/ (the O'Kelly Variation) which can restrain some of White's longer-term plans and provide the springboard for a b5 advance, though it neglects the centre.

There are many slightly different Sicilians with similar plans for Black, in which various combinations of these moves may turn up in almost any order.

The one significant departure from the main lines is /2...Nf6/, evoking Alekhine's Defence by attacking the e-pawn to tempt it forward.

Theory table
'''1. e4 c5 2. Nf3'''


text:
Chess Opening Theory/1. e4/1...c5/2. Nf3/2...d6

=Open Sicilian= Black's 2...d6 gives them the option of several popular attacking lines, controls the e5 square, supports the c-pawn and activates their queen's bishop.

White's rationale for playing 2. Nf3 was to support a /3. d4/ advance which they may now play. Their best alternative to this, for rapid development, is /3. Bb5/+, forcing Black to block the check with a minor piece that would then be pinned to the king. Swashbuckling players might be tempted by /3. b4/, planning an unopposed d4 when the Black c-pawn is diverted to b4.

Theory table
'''1. e4 c5 2. Nf3 d6'''


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Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Bc5/4. b4

= Evans Gambit = The Evans Gambit is an opening out of the Giuoco Piano variation of the Italian game. The first recorded usage of the gambit is from 1824 when a Welsh sea captain with the surname of Evans played it in a tournament. This new gambit received lots of attention, leading to lots of open, tactical games and more importantly opportunities for sacrifices favoured by chess players of the era, who preferred quick, sacrificial games over long positional games.

The gambit was first analysed in 1823 and became the mainline of 1. e4 e5 for the rest of the XIX century. Many miniatures, like the Evergreen game were made out of it. What could possibly go wrong?

Before we continue its history, let’s quickly examine its 2 lines. The line preferred by romantic players is the Slow Line, castling before pushing d2-d4. There is another line that will turn out to be objectively better, the immediate d4.

However, in the latest parts of the XIX century, Wilhelm Steinitz quickly rose to becoming the best player in the world. He uncorked a new positional style of play, aiming for long term advantages instead of attacking all the time. This style of play was proven to be effective and was taken up by many players. This was a blow to the Evans gambit, because its effectiveness was dampened when Black won’t give it the tactical game it so desires. However, the real killer came in the dawn of the twentieth century. World Champion Emmanuel Lasker invented a defense to the Evans gambit named after him. His style of play was positional, inspired by Steinitz. The Lasker Defense was brutal as it let white regain the pawn, only to suck the energy out of their position by trading queens. Bad for the Gambit player.

The Evans Gambit was killed, at least the slow line. The Evans Gambit was briefly revitalised in the interwar period, when in the immediate d2-d4 line, Sevielly Tartakower came up with the Tartakower Attack, which is 7.Qb3 in the mainline for that variation. This turned out to be the best variation. Unfortunately, the Italian Game and 1.e4 itself died out in favour of the positional Queen's Gambit and the modern 1.Nf3, and with it the Evans Gambit.

The future was bleak for the gambit. However, Garry Kasparov played it against Vishwanathan Anand, increasing its popularity. That was not enough as the Evans Gambit remained to be a second-rank choice in master level.

4.b4
White offers a pawn to gain a positional advantage in the center. Should Black accept the gambit with /4...Bxb4/, White would begin launching an attack in the center with 5. c3 and later on, 6. d4.

Theory table
.

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4


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Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Bc5/4. b4/4...Bxb4

= Evans Gambit Accepted =

4...Bxb4
Black has accepted the gambit and needs to play accurately now.

White can win a tempo in the fight for the center by playing /5. c3/.

Theory table
.

 * 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. b4 Bxb4


text:
Chess Opening Theory/1. Nf3/1...c5

=Sicilian Invitation (Réti Opening)=

1...c5
Black invites white to transpose into the Sicilian Defence with 2.e4. White has a number of other choices here. 2.c4 transposes into a Symmetrical English. Many other moves are possible—the position is still very flexible for both sides.

Theory table
.

1. Nf3 c5

title: Chess Opening Theory/1. Nf3/1...c5


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Chess Opening Theory/1. d4

1. d4 · Queen's Pawn Opening
1. d4, known as the Queen's Pawn Opening, is a popular initial move in chess, ranking second only to 1. e4 in terms of games played. It is a cunning move by White to control the center of the board and prevent Black from easily playing ...e5. Additionally, it discourages Black from developing their b8 knight to c6, where it could be vulnerable to White's pawn advance to d5. The development of the c1-bishop is not a priority for White at this stage. Instead, 1. d4 is aimed at slowing down Black's development rather than accelerating White's.

At this point, Black must decide how to face White's aggression. Traditionally, the two most popular replies are /1...d5/ and /1...Nf6/, as most other moves tend to allow White a broad center with 2. e4. Allowing the broad center was frowned upon in classical times, but is more of a matter of preference today. Another reason /1...d5/ and /1...Nf6/ are the main replies considered is that many of the alternatives transpose into main lines anyway. One notable exception is the Dutch Defense (/1...f5/), whose character prevents 2. e4 whilst remaining unique. /1...d5/ directly challenges White's plan to establish a broad center with a 2. e4 follow-up. If 1...d5, White can instead play 2. c4, the Queen's Gambit, hoping to divert Black's pawn from its job of attacking e4. The Queen's Gambit is the champagne and caviar of White openings and is a huge reason for the popularity of 1. d4. /1...Nf6/ prevents an immediate 2. e4 while maintaining flexibility to play a number of Indian systems or move back into a system typical of /1...d5/.

To play 1. d4 correctly, the White player should learn the basic Queen's Gambit positions, the King's Indian, Queen's Indian, Nimzo-Indian positions, and even some of the Benoni positions. This may seem intimidating to the beginner, but fortunately it is not as difficult as it may sound at first.

Furthermore, there are several practical advantages to becoming familiar with playing 1. d4 as White:
 * 1. d4 openings tend to be more forgiving than 1. e4 openings so far as traps are concerned. Pieces should be mobilized quickly, but it is less common for a natural-looking move to lead to a sudden demise, in contrast to several 1. e4 traps such as the Philidor Defense, Hanham Variation.
 * While there are many transpositions between the different 1. d4 openings, this is true because the underlying strategic goals are very similar. The Queen's Indian has much in common with some of the main variations of the Queen's Gambit Declined — much more so than the typical Caro-Kann has with the French Defense or Ruy Lopez in the 1. e4 world.
 * Today, at master level, the 1. d4 openings are more frequently encountered than 1. e4 openings, though the reverse is true of amateur level. 1. c4 and 1. Nf3 frequently end up transposing to a 1. d4 opening.
 * In world championships, 1. d4 openings are encountered 5 times as much as 1. e4 openings are.

Statistics

 * Approximate chances*
 * White win 38%, Draw 33%, Black win 29%.

 * Estimated next move popularity
 * Nf6 52%, d5 28%, e6 6%, g6 3%, d6 3%, f5 3%, c5 2%. Other moves 1% or less.

*May vary according to rating, higher rating groups tend toward draws at higher rates than others

Theory table

 * 1. d4

title: Chess Opening Theory/1. d4


text:
Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6

3... Nf6 – Two Knights Defence
The Black Knight move 3... Nf6 announces the Two Knights; this aggressive defence results in open and often complex play. David Bronstein suggested that the term "Chigorin's Counterattack" would be more appropriate and this is certainly borne out with current theory. The Two Knights has been adopted as Black by many aggressive players including Chigorin and Keres, and World Champions Tal and Boris Spassky.

Theory table
.
 * 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6

Statistics

 * Estimated next move popularity
 * d3 47%, Ng5 24%, d4 15%, Nc3 10%, O-O 2%, Qe2 1%


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Deving The XGameStation

The XGameStation (XGS for short), a one-of-a-kind do-it-yourself game console, was created by André Lamothe. In this book we hope to teach the user of this system to develop for it both in hardware and software. However, this book does not aim to teach what is already found in the XGS eBook. That means this book will not talk about subjects such as the design of the system itself. Instead, the book will focus on things like:
 * Writing a Keyboard Driver
 * Building an interface to NES Gamepads
 * Playing songs using the built-in hardware
 * Developing a card for use in the Expansion Slot

Hardware Deving

 * Wiring up some LEDs
 * Home-Made Tone Generator
 * Hooking up other Joysticks/Controllers (NES?)
 * Interfacing with LCDs

Software Deving

 * Creating Your First Program
 * Making it play a tone
 * Advanced use of Sound Hardware
 * Programming the SRAM Hardware
 * Programming the Joystick Hardware
 * Programming the Video Hardware

Meta

 * Editing Guide (Read before editing!)
 * List of Contributors

title: Deving The XGameStation


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Chess Opening Theory/1. e4/1...e6

1... e6 - French Defence
After 1. e4 Black plays e6 signifying their intent to play the French Defense. The move 1... e6 bolsters support for the coming advance d7-d5, providing Black with a good stake in the center and allowing Black to decline recapturing with the queen after the plausible continuation exd5. In most lines White will follow up with 2. d4, with Black's only serious reply to this being 2... d5 (over 154 times more popular than 2... c5 in master play.)

title: Chess Opening Theory/1. e4/1...e6


text:
Chess Opening Theory/1. e4/1...e6/2. d4

2. d4 - French Defence
One of the more common responses to Black's intended French Defence. White creates the ideal pawn center with pawns on d4 and e4. This allows White to control the center and develop Bishops and Queen actively. The French Defence goes on with 2... d5.

title: Chess Opening Theory/1. e4/1...e6/2. d4


text:
Chess Opening Theory/1. e4/1...e6/2. d4/2...d5

=French Defence= By advancing the d-pawn two squares, Black poses an immediate challenge to the powerful white center. White has a number of responses:

3. Nc3: There is a large amount of complex theory behind this move. Black has many possible answers, including 3...Bb4 (the Winawer Variation), which leads to extremely complex positions (which are usually closed).

3. e5 (Advance Variation): White advances the pawn and puts immediate pressure on Black's kingside, but Black will be more than capable of putting the pawn wedge under serious attack with moves like c5, Nc6, Qb6, and Nf5 after Nh6.

3. Nd2 (Tarrasch Variation): This is less common than 3. Nc3, as it blocks the bishop on c1 and does not put any pressure on d5. It is much safer but also less ambitious and harder to get an advantage with. Black has two main options here: they can play 3...Nf6 to force 4. e5 and then attack the pawn wedge at both base and head with the breaks c5 and f6, or they can play 3...c5, eventually ending up with active pieces while dealing with an isolated d-pawn.

3. exd5 (Exchange Variation): This is unambitious and gives Black equal chances, but it avoids the complications of the other variations.


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Chess Opening Theory/1. e4/1...c5/2. Nf3/2...d6/3. d4

= Open Sicilian = The aggressive advance of White's d-pawn forms a classical centre (pawns on e4 and d4), a strong formation which threatens to gain a large space advantage by a subsequent d5 or e5. Black is therefore compelled to break up White's centre.

In the Sicilian, this is easily achieved with the exchange /3...cxd4/, the control of d4 being the major reason the c-pawn was moved to c5 originally. With this natural move Black acquires a majority of central pawns and half-opens the c-file.

Their other means of attacking the centre pawns is with /3...Nf6/, in an attempt to avoid the Maróczy Bind by tempting the b1 knight out, but White can simply take the c-pawn with quicker development.

/3...Nc6/ invites either d5 or dxc5 with a strong initiative.

Theory table
.

'''1. e4 c5 2. Nf3 d6 3. d4'''


text:
Deving The XGameStation/Your First Program

Welcome to the first software development chapter of the book! To start this exercise you must have at least the following equipment:

 * An XGameStation
 * A Home PC
 * The XGameStation Development Toolchain

The Development Toolchain can be found at http://www.xgamestation.com/ under the downloads section. The XGameStation itself costs $199, and you're on your own as to a Home PC. I myself have no experience with the Linux version created by a user - (Someone enter information on it here).

First of all, plug your XGS unit up to the power adaptor and into the wall. Then use the parallel cable provided with it and connect it to LPT1 of your computer. Finally, start the XGS IDE.

In this exercise we will create the most simple program possible that will give immediate feedback. First, Wire an LED up. It should be connected between rb.0 and ground. Be sure to check the datasheet for your LED so that you have it properly biased, as putting it in backwards won't work! Also, make sure to put a 330ohm resistor in series with it to limit current. Not doing that will result in a burned out LED or even damaging a battery in some cases! Let's start by entering this simple program into the IDE:

Now, hit the 'Assemble and Run' button on the Toolbar. If everything is connected correctly and you typed the program in correctly, it should say 'Programming Successful'. Now turn on your XGS and switch the SYSMODE switch to 'RUN'. Hit the Reset button. You LED should light up!


text:
Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nf6

= Russian game =

2...Nf6
The Russian game (or Petrov's Defence) is a solid response to White's 2. Nf3. While this opening is often drawish and boring, it is still popular, and quite often played in chess tournaments. White has a couple of good responses here:

 * /3. Nxe5/ is the main line (or Classical Variation). If ...Nc6 is played afterwards, it will most likely be the Stafford Gambit. In this line, it's not advised for Black to take White's pawn before having chased the knight. There is a famous trap : 3...Nxe4? 4. Qe2 Nd6?? (or 4...Nf6??) 5. Nc6+ and Black's queen is lost. There are a few lines that are quite dangerous in the Classical Variation, especially the Cochrane Gambit, which goes 3...d6 4. Nxf7, sacrificing a knight for two pawns and an exposed king. Rarely do games in the Cochrane Gambit end in a draw, especially due to the attacking opportunities and aggression offered by the position as White tries to gain a pawn back (3 pawns for a knight is material equality), while Black tries to maintain its advantage of a pawn.
 * /3. Nc3/ is the Three Knights Game. Black can easily transpose into the Four Knights Game with 3...Nc6. This option is sound when White wants to avoid the sharp lines of Petrov's Defence. However, Black can avoid the Four Knights transposition with 3...Bb4, also pressuring the knight on c3 and making the game a little more active than it would be with the slow maneuvering of the Four Knights Game.
 * /3. Bc4/ leaves White's e4 pawn undefended but develops another piece aiming at the f7 square. This usually transposes into the Two Knights Defence (a variation of the Italian Game) with 3...Nc6 but can continue in its own line (such as the Boden–Kieseritzky Gambit).
 * /3. d4/ is the Steinitz Variation. Both players will usually plant their knights in advanced positions. Exchanges often occur in this line to avoid having too powerful an enemy knight in front of the king. This is a rather sharp variation of the Petrov's Defence.
 * /3. d3/ is, according to statistics, a much more effective move than it looks, though it's rarely played. White builds a strong fortress and Black is now forced to abandon the Petrov's lines and to defend his pawn.

Theory table
.

'''1. e4 e5 2. Nf3 Nf6'''


text:
Wikijunior:Solar System/Saturn/Hyperion

Hyperion is a moon of Saturn. It is completely covered in craters and spins at high speeds as it orbits Saturn.

How big is Hyperion?
Hyperion is 266 km wide.

What is its surface like?
The surface of Hyperion is reddish in colour. Some interesting features include the Bond-Lassell Dorsum, the largest ridge on Hyperion (and the only one to have a name), and the largest crater, which is 120 km wide and 10 km deep. There are also many craters on the surface of Hyperion which make it look like a sponge.

How long is a day on Hyperion?
Hyperion has a chaotic orbit. The day usually lasts about five hours.

How long is its orbit around Saturn?
It takes Hyperion about 21.28 days to orbit once around Saturn.

What is it made of?
Hyperion is made of water ice, and a small amount of rock.

Who is it named after?
Hyperion is named after a Titan in Greek mythology. He was the son of Gaia (Earth) and Uranus (Sky). He was the father of Helios (Sun), Selene (Moon), and Eos (Dawn).

How was it discovered?
Hyperion was discovered by three people: William Cranch Bond, his son George Phillips Bond, and William Lassell in 1848. Lassell discovered Hyperion two days after the Bonds, and he beat them to publication. However, all three are given credit for its discovery.

Wikijunior Sonnensystem/ Saturn/ Hyperion

title: Wikijunior:Solar System/Saturn/Hyperion


text:
Muggles' Guide to Harry Potter/Characters/James Potter

Overview
James Potter was the father of Harry Potter, the main protagonist of the series. James dies at the hands of Lord Voldemort offstage, just before the opening chapter of the first book, sets up the conflict in the entire series. James was born 27 March 1960 and died 31 October, 1981. He was 20 when his son was born and was 21 at his death.

Philosopher's Stone
Though introduced as Harry's dead father, James Potter plays no direct role in this book. His image appears in the Mirror of Erised when Harry finds it the first time at Christmas, and a large number of pictures of him are in the photo album given to Harry by Rubeus Hagrid just before Harry leaves the school for the summer. Hagrid has mentioned also that James Potter was head boy in his seventh (and final) year at Hogwarts. James apparently owned an Invisibility Cloak that was given anonymously to Harry at Christmas, and then mysteriously returned to him in May when he had misplaced it. This Cloak becomes an important tool for Harry, Ron, and Hermione in exploring the school.

''The tall, thin, black-haired man standing next to her put his arm around her. He wore glasses, and his hair was very untidy. It stuck up at the back, just like Harry's did.''

Prisoner of Azkaban
The Defence Against the Dark Arts teacher this year is Remus Lupin, who was one of James' best friends; at a number of points in the story, there is discussion between Harry and Professor Lupin about James. Additionally, the scenes in the Shrieking Shack involve Lupin, Sirius Black, and Peter Pettigrew, all James' close friends, and include a number of details about their mutual school days. One major revelation is that James was an unregistered Animagus.

When Harry, Hermione, and Sirius Black are being attacked by the Dementors, someone casts a Patronus charm; Harry initially believes it to be James.

It was also revealed at the end of this book that the form James took as an Animagus was that of a stag. This had earlier caused some disquiet to Lupin; Harry's Patronus charm took the shape of a stag, and Lupin seems to have recognized it.

Goblet of Fire
In Harry Potter and the Goblet of Fire, while Harry is battling Lord Voldemort in the graveyard, the Priori Incantatem effect causes shadows of Voldemort's victims to appear, including Harry's father (James) and mother (Lily) who speak with him. The shades gather around Voldemort, hindering his attack on Harry when he breaks the connection between the two wands, just long enough for Harry to escape.

In the book's earlier editions, there was the famous mistake of the wand order. The shadows appear from Voldemort's wand starting with the most recent and proceeding towards the oldest, but the earlier editions had James appearing before Lily, implying that he died after her. This was corrected by the author in later editions.

Harry also decides that, emulating his father, he will die fighting Voldemort, rather than hiding behind a stone, if he must die.

Order of the Phoenix
At the party held at Order of the Phoenix Headquarters to celebrate Ron's being made a prefect, Alastor Moody shows Harry a picture of the Order of the Phoenix from the time of Voldemort's first rise to power. Moody seems to think Harry will be pleased to see pictures of his parents in the Order; Harry feels that he has been ambushed by this sudden revelation.

Late in the book, Harry, while viewing Professor Snape’s memory in Dumbledore's Pensieve, watches James Potter during his school days with his best friends Sirius Black, Remus Lupin and Peter Pettigrew.

''“It was as though he was looking at himself but with deliberate mistakes. James’s eyes were hazel, his nose was longer than Harry’s, and there was no scar on his forehead, but they had the same thin face, same mouth, same eyebrows. James’s hair stuck up at the back exactly as Harry’s did, his hands could have been Harry’s and Harry could tell that when James stood up they would be within an inch of each other’s heights.”'' (Page 641 of the US edition)

In that memory, Harry sees his father, apparently unprovoked, tormenting Snape. The current-day Snape catches him and hauls him bodily out of that memory. Harry is deeply disturbed by what he saw, his perception of his father radically changed. He remembers Snape's earlier statement that James had almost managed to get him killed, and wonders where the truth lies; he himself would never have behaved as his father did, and yet everyone tells him James was such a good person.

Harry broods for a long time over this revelation, eventually breaking in to Professor Umbridge's office so that he can talk to Sirius Black via the Floo network. There, speaking with Sirius and Lupin, Harry learns that the memory is accurate, but that James matured into a kind and compassionate man. This hardly consoles Harry, though, realizing he is the same age James was in the memory, and that he is not beating up his fellow students.

Half-Blood Prince
Harry mentions, after Dumbledore's funeral, that he has to visit Godric's Hollow, as that is where everything began. He feels, among other things, that he must visit his parents' graves.

Deathly Hallows
Harry learns that Albus Dumbledore once lived in Godric's Hollow, just as Harry's parents had, and also that Bathilda Bagshot still resides there. Bathilda, old as she is, may remember details about the Potters and Dumbledore that she can share with Harry. Though Harry decides to visit Godric's Hollow, circumstances prevent his doing so until Christmas. In the meanwhile, he finds a letter his mother wrote to Sirius in which Lily says that Dumbledore borrowed James' Invisibility Cloak.

Harry and Hermione arrive at Godric's Hollow on Christmas Eve. Crossing the village square, Harry sees that the war memorial, to a Wizard's eye, contains a statue of his parents and himself as a baby. He locates his parents' gravestone; Hermione creates a wreath of roses to lay upon it. Leaving the village, Harry finds the Potters' cottage; it has become a makeshift memorial, with the cottage's wall still bearing the scars from Voldemort's attack.

As they escape Godric's Hollow, Harry sees, through the shared link between his and Voldemort's mind, Voldemort's memories of the night his parents were murdered. James, caught unaware by Voldemort and without his wand, had fallen almost immediately.

When Harry, Hermione, and Ron visit Xenophilius Lovegood, Harry learns that his father's Invisibility Cloak is probably one of the three Deathly Hallows. Because it was such a unique artifact, Dumbledore had borrowed it, wanting to study it. We will learn that Dumbledore, as a young man, was fascinated by the Hallows, and was unable to pass up an opportunity to investigate the Cloak, just as he was with the third Hallow later.

Harry eventually learns that his fate is inextricably entwined with Voldemort's, that he must face, and be killed by, Voldemort in order that Voldemort might die. His fear is too great to allow him to pass the Dementors guarding the Forbidden Forest, so using the Resurrection Stone, Harry summons the shades of his parents, Remus Lupin, and Sirius Black to sustain him as he goes to meet his "death". Upon reaching the clearing where Voldemort awaits, he deliberately drops the stone, releasing the four shades.

Strengths
It is implied by those who knew him that James was a powerful and talented wizard, able to master the Animagus transformation at fifteen. He was also mentioned to have high skill in transfiguration. He also co-created the Marauder's Map with Sirius Black, Remus Lupin, and Peter Pettigrew. From the Prophecy, we understand that he defied Lord Voldemort three times, though no details are given as to how that happened. Remus Lupin has stated that he had been one of the cleverest Hogwarts students of his time.

Weaknesses
According to Remus Lupin, James' ultimate downfall was his trust in his friends, as he was betrayed by his close friend, Peter Pettigrew. It is possible that another weakness was concern for his wife and son, as he sacrificed his own life in an attempt to give Lily time to get baby Harry to safety.

Relationships with Other Characters
James married Lily Evans, who he met at Hogwarts. They had one child, Harry.

During his time at Hogwarts School of Witchcraft and Wizardry, James was popular with other students, though he could be a rather arrogant bully. He, with active assistance from Sirius Black, and acquiescence from Remus Lupin and Peter Pettigrew, often tormented a classmate, Severus Snape, resulting in Severus' permanent and unreasonable hatred for James, and later, Harry.

James was a devoted and loving husband and father who cherished his son, Harry. A letter that Harry found at Number 12, Grimmauld Place, indicated that James would often play with baby Harry.

Analysis
We see James in two quite different lights. In Severus Snape's memories, from his first encounter with James in their mutual first year at Hogwarts up until "Snape's Worst Memory" in their fifth year, James was arrogant and a bully. Remus Lupin admits to Harry that this was how James behaved but had later chosen to mend his behaviour, becoming a self-sacrificing, caring and intelligent man who was extremely loyal to his family and friends. James was also mischievous and had a good sense of humour.

During James' teenage years, he had tried to attract Lily Evans' attention, but she ignored him, turned off by his bullying nature. Apparently, though, in his final two years at Hogwarts, he matured enough to show his sensitive side. We never see this, but James could not have remained the bully we initially see, and yet been the compassionate man Remus and Sirius describe, and certainly Lily would have remained aloof. However, James and Lily married shortly after graduating Hogwarts, and together joined the Order of the Phoenix, and had a son, Harry Potter. It was for his family's sake that James died, trying to give Lily enough time to escape with Harry.

Harry was frequently told that he physically resembled his father. Based on others' recollections about James, Harry built a rather idealized image of him. But when Harry learned that fifteen-year-old James often bullied weaker students, including Severus Snape, the disillusionment proved difficult for him to deal with, though he still loved his father. Harry later accepted that his father must have matured beyond his earlier bad behaviour in order for his mother to have married him.

Greater Picture
When Harry summoned James' spirit with the Resurrection Stone, James told his son how extremely proud of him he was, that he loved him, and would remain with him until his life ended.

Throughout the series, we see Harry's image of his father mature as Harry matures himself. Hagrid's initial description of James and Lily leads Harry to form an idealized image of his father, one which is seriously shaken by the revelations in Snape's Worst Memory. Harry is unable to get past this new image of James as a bully, in part because of sudden revelations concerning Dumbledore's past at the start of Harry Potter and the Deathly Hallows, until very nearly the end of the series; in this, he is helped by the resolution of his worries about Dumbledore's past. It is only with Aberforth's illumination of Dumbledore's personal history that Harry starts to apply the aphorism, "knowing people by their choices," to his father and Dumbledore. By the end of the series, Harry's image of his father has become much more balanced and true to who we believe James actually was; Harry has grown out of his childish hero worship, and gained an understanding of the path that shaped James.

The absence of Harry's father makes his adoption of a series of father figures seem realistic. We can see that Harry tries to cast first Hagrid, then Lupin, into that role with limited success; then Sirius, with slightly better results; and finally, Dumbledore. Mr. Weasley provides some fatherly characteristics as well, particularly during the Quidditch World Cup in Harry Potter and the Goblet of Fire. One of the author's strengths is the way she is able to make Harry's unconscious search for someone to replace James in his affections seem natural, keeping it low-key enough that it doesn't intrude upon the story, while still making it apparent to the reader.