matte objects and shadows not cut from alpha shadow catcher

[robert_massimi]

I'm not certain this is a bug, but it feels like it might be.
I need some help understanding the workflow for rendering with matte shadows in vray. for instance; i want to render animated people separate from the back plate renders. but ive run into a problem with the shadows. when your objects are set to matte, so they dont render, they also are ignored for shadows. so in the final comp, the people are still casting shadows, while they are in a shadow area. the shadow in the alpha, should be occluded by the matte object, just as the matte object occludes the persons head. however it does not seem to work that way. how can i have my shadows also affected by matte objects? otherwise i get a doubling of shadows in the comp. which is obviously unrealistic.

why would the matte object not also cut the shadow from the alpha? since it cuts objects from RGB. am i doing something wrong?

[hermit.crab]

It's expected for matte objects not to cast shadows, but to catch them. Is the object above the woman matte? If so, uncheck the matte option and make it invisible to the camera - this way it'll cast shadows and not be visible.

[kosso_olli]

If so, uncheck the matte option and make it invisible to the camera - this way it'll cast shadows and not be visible.

In that case, the plane will not occlude the bikers head, no?

[hermit.crab]

It's expected for matte objects not to cast shadows, but to catch them.

Correction - mattes do cast shadows through the "No GI on other mattes" option, though they are GI shadows.

In that case, the plane will not occlude the bikers head, no?

Yes, it will not occlude it. If that's the case the object must be visible but adjusted so it projects the background behind it. Here's a simple setup with this happening, although I'm not sure if it will be helpful for robert_massimi.