I knew I’d not only get an answer but a complete solution to my black lines problem with mental ray, when I ask no other than the big Mr. Zap himself!
He pointed me to a discussion of this issue in mental ray, which turned out to be a NaN issue in floating point value pixels. Thankfully, there also was a solution to this problem, which was to use, one of mr’s great features and advantages (custom shaders), a Lens shader written by David Landier.
This, D3DBlackSpotsRemover lens shader does a simple math to check for a value of each pixel and fixes it if it finds a deviation.
Thankfully, this bug has been fixed in 3ds Max 2010,
but I’m yet to test it out to see for myself and seems to be working just fine, which is awesome news! Anyways, big, big thank you to Master Zap and David Landier of course, they’re the men when it comes to mental ray!
Edit: Sorry for not posting the direct link to the shader, here it is over at David’s site.
The site is a bit confusing, so I took the liberty and mirrored the shader on my server, without permission however, so if you read this, David, and don’t want me to mirror your shader, let me know and I’ll take it down immediately.
Here’s the mirror: DL3D_BlackSpotsRemover
And here we go again.
This is another of those errors I can’t seem to get rid off. It’s not as severe as in the previous example, but still annoying as hell.
The problem is that mental ray renders pure black pixels or lines, completely randomly. It doesn’t write them in the alpha, though, but writes them in the beauty pass. Sure enough, with motion blur and everything, you can pretty much get rid of these bugs, but sometimes the errors are much larger than that and become extremely difficult to get rid of. Like in here:
Another of those errors… I hate mental ray.
Having to work with mental ray on the current project has been the most painful experience I’ve had in a long time. The countless crashes, low quality and constant “bugs” during the rendering almost drove me mad! mental ray is a strange renderer. It has some amazing features, but at the same time it lacks so much functionality and then there are the bugs (random black pixels or random black lines over your renders, unpredictable crashes etc…). I really hate it and can’t wait for this project to come to an end and I’ll be able to go back to my beloved finalRender Stage-1 and Stage-2 (for Maya).
The materials are back on-line! I’ve decided to move these downloadable materials here, so that anyone can download and use them as they like! I was quite surprised by the response I got from people around the world when I temporarily took the materials down from my business web site, duber.cz, so here they are in their original form in one, convenient, package:
finalRender Stage-1 material set 01 (requires WinRAR to unpack)
Here are the preview renders of the materials included in the package (Black Car Paint, Red Car Paint, Glass, Chrome, Ice, Stainless Steel, Wax and X-Ray)
One last note about usage, all the materials are provided under the Creative Commons licence!
finalRender Stage-1 material set 01 by
loocas duber is licensed under a
Creative Commons Attribution 3.0 Unported License.