The General Parameters rollout for both photometric and standard lights lets you turn shadow-casting on or off for the light, and choose which type of shadow the light uses.
Shadow Types and the Active Renderer
The renderer you use also affects your choice of a shadow type. The scanline renderer does not generate mental ray Shadow Map shadows, while the mental ray renderer does not support Advanced Ray-Traced or Area shadows (but it can generate area shadows: See the "Notes," below).
The Quicksilver hardware renderer always casts shadow-mapped shadows. These shadows are adaptive, and adjust to the scale of the scene: They never show the jagged edges that can appear on scanline-rendered shadow-mapped shadows if you choose an inappropriate shadow map size. The Quicksilver renderer supports most of the shadow controls associated with light objects. The exception is that it does not support patterned shadows (Shadow Parameters Map). Area lights can cast soft-edged shadows.
The iray renderer always casts ray-traced shadows. It ignores the shadow controls for light objects: With the iray renderer, all geometry is shadow-casting and all shadows are physically accurate.
Shadow type | Scanline renderer | mental ray renderer |
---|---|---|
Advanced Ray-Traced | Yes | No |
mental ray Shadow Map | No | Yes |
Area | Yes | No |
Shadow Map | Yes | Yes |
Ray-Traced | Yes | Yes |
The following table describes the advantages and disadvantages of each shadow type:
Advanced Ray-traced shadows are similar to ray-traced shadows; however, they give you more control over shadow behavior. Additional controls are available in the Optimizations rollout.
The Area Shadow generator can be applied to any light type to achieve the effect of an area shadow effect. In order to create an area shadow, the user needs to specify the dimensions of a virtual light created to "fake" an area shadow.
The Optimizations rollout provides additional controls for Advanced Ray-traced Shadow and Area Shadow generation.
Choosing “mental ray Shadow Map” as the shadow type tells the mental ray renderer to generate shadows using the mental ray shadow-map algorithm.
The Ray-Traced Shadow Parameters rollout appears when you have chosen raytracing as the shadow-generation technique for a light. You select this in the General Parameters rollout.
The Shadow Map Parameters rollout is displayed when you have chosen shadow mapping as the shadow-generation technique for a light. You select this in the General Parameters rollout.