Heya
Was just setting up a test scene for some shader tests and I run in to some weird problem with my matte shadow shader… it has some issues in RT example as well as in Production render…
Nightly from 20130318
Any help would be great ! 
Attaching images…
thanks, bye.
Hi,
It seems that setting the DMC sampler to 1/1 min/max samples doesn’t let V-Ray make enough samples to clearly show the shadow on the matte surface (for the production renderer). If you increase the max samples a bit it will render correctly. As for the problem with RT, it is an existing issue that unfortunately is not fixed yet, i.e. matte surfaces will not work with RT when using a dome light. You’ll have to disable the dome light and rely on the environment overrides.
Heya
mmm fascinating! Thanks very much !
Will work around it for now, thanks.
Is there any ETA For fix maybe?
Thanks, bye.
Howdy
Bump on the matte shadow issue. I got another one… It appears that the matteshadow is blocking all light from under the plane… which is something that I would not expect to happen. Id imagine it should only block light where shadow is but from other places where there is no shadow the light should just come through. So if I use IBL I get light coming from floor etc etc.
We tested it with Mental Ray and it give us the same result as Vray BUT when we tested it with Vred we get light coming from areas where there is no shadow so I think there might be an issue…
Thanks, bye.
Shadows link and lights link ?
How what when ? - you mean disable shadow link from from that plane with the light or eee? I’m confused.
Were also discussing the same issue in MR topic my coworker made in MR thread. The same thing happens in MR and it looks like only Vred is properly rendering shadow material.
http://forum.nvidia-arc.com/showthread.php?12348-mip\_matte\_shadow-feature-request&p=44957#post44957 #8 post for vred example
Thanks, bye.
Hi again,
As bigbossfr suggested, if you break the shadow links between the bottom light and the plane, light will hit the cylinder.
Heya
Yes it will. But will the light be reduced by the shadow? If I do the same thing for Dome light. Will the dome light be reduced by the shadow that is cast by IBL and pass where there is no shadow?
The idea is to get the light from under the plane but to block it where it has to be block by matteshadow.
I’m not sure if I’m getting the result you’re after, but with GI enabled, it seems light is slightly reduced. Your bottom light is very very intensive and where it directly hits the cylinder, everything is burned to pure white, but the falloff (indirecti) lighting on the sides is less with GI. Maybe there is another way of achieving this that I can’t figure out at the moment. All in all, I’m not completely sure that this would be possible.
Heya
So I made some more tests. And when I baked the shadow and used is as a opacity texture in shader then the render “more” correctly.
Have a look at the scene (sorry for the yesterday one, just realized how messy I send it 
) In any case I had to move light a little bit to show the result.
With baked shadow I get +/- what I would expect to happen from matte shadow.
02.mb.zip (26.7 KB)
Yes, that was the next suggestion I was going to make. Is this going to work for you?
My personally… I could sort of slide it under the carpet and work this way. But for company and production work with clients… not really.
If we do a lighting session with client and they accept the look they see. Then we cant come back latter and correct it because it will be different from aproved look.
So the RT light issue(in 1st post) is my 1st priority and the light coming from under plane is my 2nd priority tbh.
Its just 2 bugs I hope chaos will be able to fix it at some point so we can move on to other matters.
Thanks for your help.
Thanks, bye.
Those are already logged in our bug tracker and we will let you know when we have them fixed. We’ll also look into getting the opacity/shadow light blocking/reduction.
Thats awesome!
Thanks you very much for your help and info.
Thanks, bye.
