vray Light matterial plus matte doesn't affect shadows?

[lukx]

Got question.
Scene with plane and box on top of it. Plane is matte object with alpha -1 and shadows on plus affect alpha. Over box I setup vraylight and when looking at alpha shadows are there. Now When instead of vraylight I put plane with vrayLight mat it cast shadows on plane but it deson't show in alpha. Am I doing something wrong or it's how it works in vray?

[vlado]

This is how things work; when you have a VRayLight, V-Ray knows how to determine what is shadow and what is not so that it can modify the alpha of the matte object accordingly. But with GI, there is no such information available; the only thing that V-Ray does in this case is to calculate the occlusion from the environment.

Best regards,
Vlado