Real Time 3D Jargon “Cheat Sheet” Compiled by Christina Ellison.

Camera: In RT3D, this is another word for the viewer's view into the scene.

· Camera target (interest): Where the camera points at.

· Angle: Field of view (fov) in degrees. 30 corresponds to the normal lens of 35mm still camera.

· Pan: Rotating camera along vertical axis, i.e. moving camera target sideways.

· Roll: Rotating camera along the line of sight. If animated, a swaying effect is achieved.

· Tilt: Rotating camera along the axis perpendicular to the line of sight, i.e moving target vertically. If animated, a nodding effect is achieved.

· Zoom: Changing the field of view.

· Dolly: Moving the camera along the line of sight, i.e close and far from the target. Term originally refers to the carriage under the camera stand, pushed on wheels along rails.

Direct3D: Microsoft's API for 3D graphics. One of the components of DirectX. Supported by all gaming-oriented 3D accelerators so far. DirectX a set of APIs developed by Microsoft. DirectX is made of several components, each of which can be used to access different hardware devices. The members of this family include: Direct Draw for enhanced 2-D graphics services. Direct3D for enhanced 3-D graphics services. Direct Sound for enhanced sound-mixing and playback services. Direct Play for enhanced multiplayer game connectivity over the Internet. Direct Input for enhanced joystick and other input device performance. DirectX is a low-level API designed specially for high-performance applications such as games. It is a thin layer providing direct access to hardware services (hence the name). The technology takes advantage of available hardware accelerators and emulates accelerator service when accelerators are present.

OpenGL: OpenGL is a graphics SDK for PCs and Macs used to develop 3D games like Quake. A software development kit or SDK is a tool that programmers use to develop games without having to write hardware or hardware emulation code from scratch. Instead they can use function calls to the SDK library of pre-defined hardware and hardware emulation code. DirectX and OpenGL are both popular SDKs that game programmers use. OpenGL is a set of specifications for a cross-platform 3D graphics API developed initially by Silicon Graphics Inc. Currently this is primarily used for CAD applications and other professional level 3D design work in Windows NT. Quake has popularized this as a gaming API. For PC 3D graphics accelerators, there are currently two ways to implement OpenGL support, a full Installable Client Driver (ICD) or a Mini Client Driver (MCD). ICD is the original driver model for OpenGL, and enables vendors to access the entire OpenGL pipeline, allowing them to increase acceleration while maintaining the stability and compatibility of the driver. MCD is a stripped down OpenGL driver, allowing access to only a portion of the OpenGL pipeline, limiting the ability to increase performance and stabilize the driver. MCD is all that is required for games such as Quake.

Particle Systems: "Non-volume, non-surface 2D pixels in 3D space, often used in multitudes. Particles' behaviour is affected by the natural forces such as gravity, winds, collisions to other objects and group dynamics: all properties of a group of particles can be defined by a mean value and a deviation, resulting in flock behaviour. Useful in visualizing 'non-material' natural phenomena such as snow, fire, smoke, grass and hair. Unfortunately, particles usually have to be rendered separately from the rest of the scene and composited later. Developed by Karl Sims of Thinking Machines Corp."

Real Time: When events happen at a rate consistent with events in the outside world. Specifically for RT3D artists, if the engine renders a scene at a slow rate, the illusion of movement can be lost. To retain an interactive, immersive experience, the engine must react to your input and present you with new updated images immediately. If you are getting smooth feedback, it is real-time. Frames per second is the measurement of how fast the frames

are being rendered. The engine must perform many complex operations, and the effect of that effort is the amount of time needed to draw each frame. By necessity, we must take shortcuts in the image quality to speed up the rendering. However, no single image remains visible for very long. If you carefully choose speedup techniques so that the errors are small, then they will not be noticed during the moment when the picture is visible.

Real Time 3D (or RT3D): Real-Time 3-Dimensional graphics. Artwork that is rendered in real-time on a computer, usually with interactive input from the viewer.

Texture Mapping: In 3D graphics, texture mapping is the process of adding a graphic pattern to the polygons of a 3D scene. Unlike simple shading, which uses colors to the underlying polygons of the scene, texture mapping applies simple textured graphics, also known as patterns or more commonly "tiles", to simulate walls, floors, the sky, and so on.

Method for wrapping 2D pattern or image around the 3D surface. Texture mapping can dramatically add realism even to a most rudimentary geometry.

Projection

Method describing how the texture is wrapped around the object:

Planar

For flat objects.

Cylindrical

For cylindrical objects.

Spherical

For spheroid objects.

Auto

Automatic projection for complicated objects.

Texture sources are typically:

· 2D texture: Typically an image from various sources: painted, scanned, rendered, etc.

· 3D(procedural) texture: Random patterns (such as marble, wood and clouds) generated by mathematical algorithms.

Mapping can be input to various shader parameters:

· Transparency mapping: Mapping is directed to effect on the object transparency: white areas derived from the texture image become transparent, black areas stay opaque.

· Bump mapping: Mapping is directed to effect on the surface normals, so that the object looks bumpy and rough. White areas in the texture image turn the surface normal to the opposite direction than black. This is only pseudo effect: it applies only to rendered images. Also, the contour of the surface remains smooth.

· Displacement mapping: Like bump mapping, except that the object surface is affected for real. Displacement mapping is only a render effect. In some cases, however, it is possible to write out the 'carved' geometry.

· Reflection mapping: Mapping is directed to reflect from the mapped object. An excellent method to reduce render time: ray tracing can be switched off and reflections are still achieved.

· Refraction mapping: Mapping is directed to refract through the mapped object. Useful method to reduce render time on transparent objects. Rarely used, though.

As a default texture mapping usually only affects color.

Viewpoint:

MIP-mapping: This is an important feature of any 3D graphics accelerator. It refers to the ability to apply a texture to a 3D object based on that object's distance from the viewpoint. This requires modification of the texture and is normally applied either on a per-pixel or per-triangle basis, with the latter being faster but less accurate.

Viewer1: You, the user of the RT3D application, looking at the 3D scene through your computer screen. The viewer looks into the RT3D world from a vantage point, which acts something like a camera, to frame your view. Most of the engine's calculations are tailored to make the world look great from that particular view.

Viewer2: A version of the RT3D engine that is used to preview artwork while it is being created.