Working with Drop Shadows
The following items support drop shadows:
** Decal Materials: ** The material thickness (a material attribute) is combined with the light vector angle (set this on the Texture tab of the Object Properties dialog box) to determine the size and position of the drop shadow for a decal object.
** Static Overlap Objects: ** The drop shadow must be built into the RGBA image, which can be imported individually or with a layered PSD file. It is saved with the vignette.