Displacement problem - haven't seen before

[tricky]

I might be having the same problem, and I am using a bitmap (no procedural maps) for the displacement. The displace map was created from high-poly models in max using a Vray Zdepth render element. I have tried playing with the filtering in the bitmap and in the Modifier, and I have also adjusted the 2Dmapping resolution/precision values and nothing helps get rid of this noise. Has anyone had any experience solving this problem?


Thanks,

Andrew

That looks like a cool way of generating those kind of details. Could I look at your z-depth map? What are render times and setup like?

[ajroane]

It would be cool ... if it worked. Really, it is a very simple set-up. The details were all modeled against a flat plane, which was mapped with a reference image (see screen shot image). Then I set up a standard max camera, and turned on 'orthographic projection.' I then created two render elements: 1) VrayZdepth, 2) VRayExtraTex with a black to white VrayDirt texture, really just an AO pass. I used the camera's clipping planes to quickly find good distances for the zdepth min/max values. The dirt texture was used in a composite map on the displaced geometry, to add more definition to the displacement.

Rendering the maps is really fast since GI is not necessary. It took 80 seconds to render the attached images. The only factor I had to adjust was the Image Sampler (AA) so that the results were smooth enough. Oh, and I also set the subd's in the dirt texture to 24 instead of 8. The AO didn't work perfectly, I need to render it with more geometry around it, so that the dirt texture can blend out more smoothly.

I used 2D mapping in the VrayDisplacementMod. I tried several different combinations of values in the resolution/precision, I think I finally ended up using a resolution of 1024 and a precision of 8. I also have the amount set to 1" and the shift set at -.1". Just for a sense of scale, the egg/dart details were about 4" tall in this test.

Hopefully that explanation makes sense. The rendered elements are posted below, I created tileable maps from these in PS.

[edit]... I hope more of you can try this out, and please let me know if you find a way to get rid of the noise on the displaced geometry, I still haven't figured it out. Thanks!

[Neilg]

I've done stuff like that before and it's worked fine :/

This might be silly, but you dont have vray dirt on the material of your displaced object do you?

[ajroane]

I've done stuff like that before and it's worked fine :/

This might be silly, but you dont have vray dirt on the material of your displaced object do you?

Nope, just the bitmap version of the rendered dirt map is being used as a mask in a composite map, so I don't think it's a diffuse texture problem. Are you using Max2011, 64-bit?

[ajroane]

What are render times and setup like?

Forgot to tell you earlier...the small test scene shown in my first post took 32.5 seconds to render. I have a single, 4-core Xeon W3520 2.67 Ghz and 12 Gig RAM.

[ajroane]

Just did another quick test to verify...so I put a simple grey Vraymaterial in the override slot and I still get the same noise problem on the displaced geometry.

[deneb26]

What color-depth is the displacement-texture saved to? try 16 Bit if it's 8 bit.

regards
ale