Problem with displace and reflection

[Mric]

Hi all,

I need your help and advices for a problem that I have not yet to find solution. In the attached file, you will see two renders and a screenshot of VrayDisplaceMod settings. The first render use a VRayMtl with reflection. The second render use a default VRayMtl without reflection. In render 2, you will see there isn't problem with displace. With the first render, I add reflections with glossy to 1 and i have problem with displace reflection. I don't find what's the problem. I think render 2 shows it's not a displace problem. I have tested different way to resolve it (antialiasing params,...) but i don't find the solution.

Thank you for your help. I forgot something but what....

Mric.

[TheLooopCGI]

What is the blur parameter of the bitmap map you use for displacement? If It's 1.0, try the lowest 0.01.

[Mric]

TheLooopCGI, i've done a render with changing the blur param to 0,01 but you can see there is no change. I've tried with a blur param 2 and no change too.

Nobody can help me solve this problem. It's urgent fot me !

Thank you TheLooopCGI and others to help me.

[TheLooopCGI]

From the small previews it's not really clear whether the same problem doesn't plague also the clay render. Did you see in high-res that the problem is really not there? It could be that the problem is in both pictures in which case it could be a texture quality problem. We sometimes have it that the photoshop artist makes a wand-tool selection and doesn't check whether the selection edge is nice and smooth in which case the problem that you have will pop-up. In any case, 2048px resolution for a displacement texture is not much.
What you can also try is a 3D displacement with a 0.5 pixel accuracy.

[Mric]

I don't think it's a hight res problem of the map. I've done a 4K size map for the displace and I have tested a render with a map size 2048 and 4096pix but always the same problem. What do you mean by "0.5 pixel accuracy" ?

[TheLooopCGI]

Right now you're using 2D displacement in the VRayDisp mod right? So try switching to 3D displacement and then you have an edge length parameter. Set this one to 0.5 and see if it's better.

[Mric]

Question : When you have a vray license, you have a support with it? Can we send a scene to chaosgroup support when we have a problem with vray like, in this case, with displacement? Because for this project i need to solve this problem quickly....!

TheLooopCGI : I've tested with displace 3Dmapping and edge length to 0.5 but always the same problem

[TheLooopCGI]

Hmm, in that case I'd see the texture as a main problem. Try to see if you really have the edges of those ridges on the texture smooth. If it's not secret you could post the part of the texture we see on the render here on the forums so I could maybe try to apply it here and see if I also have this problem.

As for your question - I don't think it is mentioned anywhere in the licence agreement that you have a right for the chaosgroup support. I think it's just a bonus for the customers as I don't see it would be practical to commit themselves to help everybody with the problems they might have in their scene which might not be caused by an error in the software itself.

[rivoli]

Question : When you have a vray license, you have a support with it? Can we send a scene to chaosgroup support when we have a problem with vray like, in this case, with displacement? Because for this project i need to solve this problem quickly....!

of course you can, it's been done thousand of times. try emailng chaos or vlado directly, I'm sure you'll get an answer fast.

[Neilg]

Have you checked the reflection depth, incase it's a shading issue with the limit?

[Mric]

http://www.megaupload.com/?d=4JUUOOM2

Here, you will find the scene with .max(2010 scene) and displace map. It's maybe a better solution for you to help me. Thank you in advance to everyone.

[TheLooopCGI]

Okay, first of all you really have to redraw your texture (redraw, not just scale up). 2000px/8bit is really not enough when you make highly reflective smooth curves like that. For the current picture resolution I recommend 4000px minimum, if you go higher for final render, go higher with the texture. And if you draw it yourself then there's no reason to stay with 8bit - go 16. TIFF is usually the best format for this - lossless compression makes the filesize reasonable and no quality loss at the same time.
After that you have to set the resolution setting inside VrayDisplacement mod higher of course. For some strange reason when I set higher then 2048px the texture kind of disappears completely. So if it's doing the same in your file, just go with 3D displacement and set the edge length to 0.5px.
Also don't forget to change the blur parameter of the bitmap map to 0.01 instead of 1.0.

What I also used was a Blend AA filter instead of the default Area. The parameters were 2.0 for size and 0.2 for blend. Should give a smoother result. Problem is that with these curves you will get some slight aliasing problems even if you would model these ridges perfectly yourself so you have to help it with the filter a bit.

[Mric]

First of all, thank you very much for your help. It's very important to have this support type. I'm going to test a render with your parameters. Your render is very good. Could you upload your scene to see that? it would be very cool. Thank you again TheLooopCGI.

[TheLooopCGI]

No problem, happy to help.

Here is the link to download:
http://hotfile.com/dl/75526269/cf674...n_new.zip.html

[Mric]

Thank you! see you soon for another problem