A

alpha channel — A fourth channel (after RGB) that can be included with 32-bit image formats and contains transparency information. See Appendix B for a list of image formats that can use alpha channels. The alpha channel within a render determines the manner in which it will blend with underlying layers when the render is put in the compositing phase of production.

C

CG — Used as shorthand for “computer-generated.” Also, any images, films, or clips created using computers.

compositing — The process whereby different elements, either filmed or created digitally, are combined to form visual effects. Popular compositing packages include Adobe After Effects, Discreet Flame, Shake, and many others. Compositing is an extremely critical part of the production process, since it is up to the compositor to ensure that the different elements and plates blend together realistically. Often referred to simply as “comping.”

F

fractal — A geometric entity characterized by a pattern that is repeated at ever-decreasing sizes. Fractal patterns form the basis for many procedural textures.

G

grunge mapping — A method of quickly creating dirt in texture maps involving the use of high-contrast and detailed gritty images that are used as overlaid blending layers or used to make selections from other layers to create new gritty-looking texture layers.

I

image map — Any image that is used as a texture on a 3D model.

image resolution — In printing terms, the resolution refers to the actual dots per inch ratio, but in broadcast production terms, the resolution of an image usually refers to the actual pixel dimensions of the frame or image being used.

interpolation — The process of estimating values between specific points. For example, UV maps use interpolation to calculate the map values across polygons since the actual set values are only initially determined at the vertices where the polygons end.

N

node — Nodes are basically data containers with inputs, outputs, or both inputs and outputs. You can connect two or more of these containers to create what’s called a network to describe the final look of the surface or light.

normal — see surface normal

P

Phong shading — Phong is the shading model that LightWave uses when rendering if it isn’t changed through the Node Editor. In order to create the illusion of shapes being smooth, Phong shading interpolates the vertex normals across the surface of the polygon and illuminates the pixel at each point.

pixel — A tiny picture element that contains red, green, and blue information for color rendering on a monitor.

procedural texture — A mathematical algorithm that creates fractal patterns that can be used as textures on a surface. Procedural textures include Fractal Noise, Turbulence, Grid, and many others.

projection — The specific manner in which an image is placed onto a model.

R

raster images — Bitmap images formed by arrays of pixels, such as those made within image editing applications like Adobe Photoshop.

S

shader — In LightWave, a mathematical algorithm that affects the way in which light reacts to a surface as a whole. LightWave’s shaders include the BRDF and Fresnel shaders, among others. Shaders can also refer to a surface as a whole or shading models.

stylus — A computer artist’s alternative to the mouse. A stylus is a pen-like computer input device used with its accompanying tablet for painting and drawing.

subsurface scattering (SSS) — This is the phenomenon of light diffusion through a semi-translucent object where light comes in and bounces within the volume of the object before it exits through a different point of the surface. A couple of good examples of this are wax and skin. LightWave has two different SSS shading models to help you simulate this effect in your work: Kappa, which is commonly called “fake SSS,” and Omega, which is an accurate, real-world model. Both of these models were written exclusively for LightWave 3D.

surface normal — A line emanating from the surface of a polygon that always lies perfectly perpendicular to the polygon. You can see the surface normals by choosing the option in your viewport display options.

T

texture map — see image map

V

vector images — Images made from lines and curves defined by mathematical objects called vectors. Commonly used vector programs include Adobe Illustrator and CorelDRAW. Because vectors are not rasterized, they can be scaled up to any size without any degradation of quality.