You can use mental ray
for Maya’s detail shadow map to render colored shadows in your scene.
This effect is driven by the transparency color of the object, like
raytraced shadows.
To render colored shadows with detail
shadow maps
- In the Scene View, select the light that
you want to use to create a shadow. The light must be a point light,
spot light or a directional light.
- Open the Attribute Editor for
the light shape node.
- In the Attribute Editor,
open the Shadows section, and set the Shadow Color.
- Expand the mental ray section
and select the Detail Shadow Map option under
the Shadow Map Format attribute
in the Shadows section.
- Select the Use mental ray shadow
map overrides option.
- Render your scene in mental ray for Maya.