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Faceted Bump and Normals in Render
Posted: Mon Jan 20, 2014 8:47 pm
by vizport
I have an issue with height maps in my render. No matter what I do they render faceted. I applied the material to a cylinder for a test. If I disable the Bump map it's gone and smooth. Even worse: if I increase the strength to 20 it renders more and more errors with streams and it seems that the whole smoothing groups were completely destroyed.
- set bump / normal to 1 - no fix
- local or global - no effect
- set material to another object - same effect
- disble the bump - everything fine and smooth
- apply turbosmooth - no effect
- apply displacement -
any idea?
Engine 3.0.0.0
Plugin 3.0.14
Re: Faceted Bump and Normals in Render
Posted: Tue Jan 21, 2014 5:38 am
by vizport
OK, after some tests it all boils down to the sheer size of the bump map which is in my case 45.0000px. And this a bug: faceted surfaces occur when you try to use a bump / normal map that exceeds certain resolution. It also depends on how high you set the power of the map. For example it's likely to happen at 100%. And 50% it starts more frequently. The problem is depending on the height of the normal map we are forced to lower the values. However you can render the diffuse and any other channel w/o problems.
here we go with a displcement of 10 subdivs
and here is the problem - a normal map@100% / smoothing group is gone
Re: Faceted Bump and Normals in Render
Posted: Tue Jan 21, 2014 1:12 pm
by Fernando Tella
I experienced something similar a while ago which I cannot reproduce it right now. It happened with a material which had 2 BSDFs with bump map on each of them. When I moved the map to the global bump map and deleted the ones in the BSDFs the problem disappeared. Maybe it works in your case too.
Re: Faceted Bump and Normals in Render
Posted: Tue Jan 21, 2014 2:16 pm
by numerobis
Re: Faceted Bump and Normals in Render
Posted: Tue Jan 21, 2014 3:02 pm
by dariolanza
Yes, this is the facetted visible in the lit-to-shaded transition that appears when the polygonalization of the mesh is poor.
Subdividing the mesh will get rid of it. This is why applying Displacement also gets rid of it.
Subdividing is the only thing you can do so far.
Dario Lanza
Re: Faceted Bump and Normals in Render
Posted: Tue Jan 21, 2014 4:09 pm
by Fernando Tella
I thought this problem was corrected in V3, but re-reading the post I notice it's a different problem:
http://www.maxwellrender.com/forum/view ... it=shading
Subdivision modifier can be a workaround in this case too.
Re: Faceted Bump and Normals in Render
Posted: Wed Jan 22, 2014 3:11 am
by vizport
Well, thanks guys for the info. I don't use maxwell for so long I that I came across every little bugger or work around.
The real shit is that the left trunk in both images is made out of a simple 3ds Max cylinder with a tesselate + noise modifier applied, the second one (more complex) comes from an imported fbx file. I'm testing now with the subdivision modifier.
Re: Faceted Bump and Normals in Render
Posted: Thu Jan 23, 2014 6:12 pm
by vizport
It seems that the problem is likely to happen when larger surfaces were used. The subdiv is no problem for me, since we have all machines @ >96GB RAM
