There are five types of lights in 3D Studio Max:
omni lights that cast unfocused light in all directions
directional lights that cast parallel beams of light in one direction
target spotlights that cast a focused beam of light towards a target
free spotlights that cast a focused beam of light in a direction
Omni lights and spotlights can be attenuated, but there is no attenuation for ambient of directional lights. The light intensity diminishes linearly between the Start Range and End Range such that it is zero at the End Range.
Objects can be excluded from lights, i.e., the excluded objects will not be illuminated by that light, but may be illuminated by other lights.
Ambient light and omni lights cannot cast shadows but the other types of light can cast shadows. Objects can be excluded from casting shadows, i.e., the excluded objects will not cast a shadow from that light, but may cast shadows from other lights.
3D Studio Max uses two possible methods to cast shadows. The first is the scan-line graphics method of creating a shadow map in a pre-rendering pass. The second method is to use ray tracing to create the shadows. The shadow map method has the advantage of being able to create soft-edged shadows, while the ray tracing method will only create hard edged shadows (so clearly 3D Studio Max does not use distributed ray tracing). The ray traced shadows are more accurate and can show the colored shadows cast by transparent or translucent objects.
Spotlights and directional lights can also project an image, e.g., just like a slide projector. The image map can be animated so that you can emulate a movie projector or a television.
Last changed November 02, 1998, G. Scott Owen, firstname.lastname@example.org
Lighting in Computer Graphics
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