This is a bug?

V-Ray V-Ray for Maya Issues
1

Learning FastSSS2, I found myself with this:

Here the scene:

Its a bug?. I don’t understand why appear almost the scatter color like gummybear foot reflection… or something more circular.

WhatsThis..jpg
WhatsThis..jpg500×700 10.9 KB

FastGummyBear.mb..zip (69.1 KB)
Original..jpg
Original..jpg500×700 17.7 KB

2

Change the “Shadow bias” for the lights to a smaller value (e.g. 0.001) and it will be fine.

Best regards,
Vlado

3

I got it. Thanks for the trick.

4

Eeeer, yes it works, but if we put the “Single Scatter” in “Raytraced (refractive)”… this remains. How we can solve it then?.

And the most important. How ever, Why?. Why this happens?. I we know why, we can avoid “being fixing errors”, because directly we don’t fall again in the same.

5

Are you sure this is a shadow issue?. If you turn off the shadow of the light, the render error still remains happening.

Here the second frame, with and without shadows:

WhithoutShadows.jpg
WhithoutShadows.jpg1280×800 190 KB

WithShadows.jpg
WithShadows.jpg1280×800 188 KB

6

Hi,

did you turn off the shadows for all the lights in the scene ? I’m seeing two lights in scene, turning off shadows for both of them and the artifact is gone for both simple and refractive modes.
Also modifying the shadow bias fixes the problem, like Vlado said, irrespective of the VRayFastSSS2 mode.

The shadow bias is there, so that artifacts (surface acne) are not present when there are overlapping surfaces in the scene. Unfortunately, depending on the scene scale, artifacts like in your case may occur. Probably we need to lower the default shadow bias value, I’m not sure. Vlado can say about that.

Greetings,
Vladimir Nedev

7

Incredible. I was me who created the test scene and I’m unable to see that I created two lights… bless patience you should have with us (me, in really, what’s auto owned!). Thanks for the hint one more time.