Material Wrapper Matte bug

[seltzdesign]

We have been trying to create some shadow catchers using V-Ray in Rhino and Grasshopper and it is driving us insane.

If I do it in a new file with a super simple setup with a sun and a box and a floor that gets a wrapper material with the Matte option enabled, then it works, but only when using the CUDA or RTX option. Using the CPU option it simply refuses to render any shadow on the shadow catcher:



As you can see the shadow catcher does not display any shadow at all. Here is the same scene rendered with CUDA:



So there is definitely a bug there, that it does not work at all on CPU.

Also, I don't understand the Matte option and why by default it looks totally different than the normal shadow, even though the shadow catcher has that same white material as its base? Shouldn't the shadow color/opacity be the same as the shadow on the white floor?

In my other file it's even worse. Not only is the color of the shadow wrong, but the shadow catcher is not even completely transparent:



Once again, switching to the CPU interactive renderer makes the shadow catcher completely transparent, but no shadow is seen.




This is using the latest V-Ray for Rhino, with up-to-date Nvidia Studio drivers.

Can you provide a simple scene with a shadow catcher that works reliably?

[slavcho.brusev]

Hi,

Please try with Matte Shadow Receiver material from the built in library. You can quickly find it if you type Shadow in the search box.

[seltzdesign]

Hi,

Please try with Matte Shadow Receiver material from the built in library. You can quickly find it if you type Shadow in the search box.

Cool, thanks, it seems to work better.

Is there a way to have the shadow catcher be transparent and show things underneath, not only the background? Or is that only possible in compositing?


Edit:

Sorry, the bug with the CPU rendering still exists:

CPU:




CUDA:

[richard_aubin]

Any update on this?