User manual

Maxwell Render 2.5 User Manual

Chapter 18. Appendix V. Glossary | 159

18 APPENDIX V. GLOSSARY

Abbe: Abbe is related to dispersion - the effect seen when a beam of light passes through

a prism and is split up into different wavelengths of light. Abbe controls the amount of

dispersion: the higher the Abbe number, the narrower the dispersion will be. If you set the

Abbe number really high, the dispersion will disappear completely.

Aliasing: The process by which smooth curves and other lines become jagged because

the resolution of the graphics device or the le is not high enough to represent a smooth

curve. This problem can be solved with anti-aliasing.

Alpha Blending: The assignment of varying levels of translucency to graphical objects.

This allows for the creation of things such as glass, fog, and ghosts. Alpha Blending can

be accomplished by using alpha channels, or through other means.

Anisotropic Filtering: Anisotropic Filtering (AF) is a method of enhancing the image

quality of textures and surfaces that are far away and steeply angled with respect to the

point of view. Older techniques don’t take account of the angle that the surface is viewed

from, which can result in aliasing or blurring textures. By reducing detail in one direction

more than another, these effects can be reduced.

Anisotropy: The property of being directionally dependent, as opposed to isotropic, which

means homogeneity in all directions. An anisotropic surface will change in appearance as it

is rotated around its geometric normal, like with velvet. In Maxwell Render the Anisotropic

material setting will create a material that is more reective in one direction, and more

diffuse in the perpendicular direction. In real life this is caused by polishing a surface in

one dominant direction, making small grooves on the surface which run mostly in one

direction.

Anti-Aliasing: This is the process that removes the aliasing effect. A ltering method is

normally used in the process that removes the “jaggedness effect” produced by pixels.

(Also see Aliasing).

Aperture: An aperture is a hole or opening through which light is admitted. In photography,

the aperture size of the lens can be adjusted to control the amount of light reaching the

lm. A diaphragm usually serves as an aperture stop and controls the aperture.