Hi all, I'm not very good with shaders so please bear with me. I have a CG vertex and fragment shader that calculates UV coordinates in the fragment shader. The mesh texture (frame of a video blit onto a texture) has an alpha channel and is mostly transparent. Based on the transparency and UV's I want to cast a shadow onto objects behind the plane (diagram attached). Things I have tried: 1. Using a basic ShadowCaster pass, this just cast a shadow of the entire plane. 2. Using standard shader with cutout, leads to incorrect shadows (I believe this is because they are vertex calculated and the whole texture is taken into account) 3. Calculate UV's also in ShaderCaster pass. Led to shader errors when trying to use unity_ObjectToWorld Things I thought about but couldn't find enough info to get it working: 1. "Pre-process" the texture and blit a "Render Texture" with a 0 to 1 mapping onto the textured plane. I got stuck on this route because vertex data isn't passed into Graphics.Blit. From what I read this is because it's designed for texture processing. Any help or speculation on how I might achieve my goal would be great!