This is my rendering of a model I picked up ready (TurboSquid, free).
Textures were in included in the download as image files. Importing the 3ds to Blender, left me with some materials (names only), no textures and all showed up as generic grays.
So I defined the materials to get the effect I wanted. I made a semi-transparent material for the interior lighter curtains, like a veil, and used an image supplied with the model as an alpha map the simulates the folds to the veil so its more tight and opaque at the top, and more spaced/curvy at the bottom hence more transparent.
The rendered image shows to my satisfaction, however the shadows do not follow-up. The light from behind the transparent veil casts a full dark shadow, just as the heavy curtains drawn to either side.
Below are the image files used and my settings. I think what I am looking for is translucency? but no such settings had an effect.
Can you help me?