Matte Shadow Receiver working strangely

[maarten_bergsma]

After updating to the newest version of Vray for Rhino, it seems Matte Shadow Receiver comes with some new / different functionality. I may be missing a step or something for rendering, but I can't seem to achieve results that I did in the past with the material... I need help to figure out what's going on.

In the attached image, I'm attempting to generate matte shadow with no affect on alpha EXCEPT where the shadow occurs. I have no idea why the matte shadow receiver surface is appearing as purple in the alpha channel. How to I stop it from rendering the entire MSR surface with translucency?

Thanks.

[nikoleta.garkova]

Hi maarten_bergsma

I've made a simple test with Rhino 6/V-Ray 5, hotfix 1 and it appears to be working as expected both on CPU and GPU - check the screen recording here: http://ftp.chaosgroup.com/support/sc...2_13-15-45.mp4

That being said, it does look odd in your scenario - does it happen with every project, even if you open a clean file and make it from scratch?
If you use Wrapper material instead, do you get the same results? https://docs.chaosgroup.com/display/VRHINO/Wrapper
Make sure that:

1. The Wrapper material's "Matte for Secondaries" option is disabled.
2. The Wrapper material's Alpha Contribution is set to "Black Alpha (-1)"
3. Dome Light is set to Spherical shape.

If there is no difference, would it be possible to specify the exact versions of V-Ray/Rhino used (you can check from V-Ray > About V-Ray)
Moreover, are you using CPU or GPU? Can you give more specifications on the CPU/GPU/GPU driver versions?
Can you provide more details on the project setup? What type of lights are used, are you using Dome Light/is it set to Spherical/is the HDRI slotted in the Environment Background slot?

If it is happening only with this particular project, best would be to reach us through our contact form and forward the files. Make sure to mention this thread in the email, thanks.

[maarten_bergsma]

Hello nikoleta.garkova

Thank you for the response. I'm glad this issue doesn't occur on your side, and I will attempt to use the settings you've described. Would it make any difference using a directional light to your knowledge? I was in fact using a directional rather than a spherical or the sunlight option. I will update you with my test later.

[konstantin_chaos]

Hi maarten_bergsma,

I also unsuccessful in preproducing the issues.
Can you please share your scene so that we can investigate on our side?

Konstantin