I have spent hours on end trying to get this render pass to work.
A live action with CG elements. HDRI environment as reflection. Vray sun for shadows.
Say you had a fully reflective chrome teapot hovering above the ground and casting its shadow onto the ground strip geometry. My problem is that I want to eliminate that plane ground in the Teapot reflection BUT keep the Shadow. therefore it looks like its on the normal (reflection environment) ground. and the normal ground is reflecting onto the teapot.
Unless I’m missing something, that looks like a basic matte situation.
Put the ground object’s material into a VRayMtlWrapper and turn on Matte Surface, adjusting the other options as needed. Then assign the VRayMtlWrapper as the new ground material. If the base ground material has any reflectivity, you’ll also have to override its environment map.
Max’s default Matte/Shadow material should also work, but gives you less control over the way alpha is calculated.
