3sdmax - Problem rendering wires with MR

3Dyan

Hey guys, I'm trying to render a wireframe using mental ray and I'm experiencing this problem:


I also tried to render using scanline (duplicated object) and the same thing happens.

For some reason this does not happen when the model is triangulated.

Any ideas?

3Dyan

Bump. This thing is driving me crazy

Lamont

This plugin has saved me quite a few times:

http://www.davidgould.com/Illustrate/Products.htm

Kroma!

Looks like you may need to increase the amount of samples you are taking.

Try using one of these materials from here.

Gives you really nice results and if you are getting faded, patchy wires then turn up the samples per pixel values. Takes longer but you get a cleaner render.

Hope this helps!

BARDLER

I do this quick and dirty thing that gives good results without having to do much.
-Save out a UV wire snapshot at like 4x resolution of your textures.
-Downsize it to whatever you need, which gives the wires nice AA.
-Overlay on AO, or apply it to the mesh with transparency so it combines with the base material.

spacefrog

Most porbably you have the minimal sampling set too low, bump that value up to be higher than 1.0 ( the higher = the better ). MR simply undersamples your wires and thus looses some pixels in specific areas..

3Dyan

Thanks for the comments, guys, but I already tried going as high as 64, and was still getting faded wires near the vertices. Final gather and GI off as well. No idea how to explain this.

Gotta resort to some other tricks like suggested, I think.

3Dyan

I tried making the wires thick to see what's going on, and this is how they look:



You can clearly see they are acting very strangely for some reason. Any ideas?

Kroma!

Try exporting the model as an OBJ then importing it again. Sometimes this fixes meshes by exporting it to a simpler format then using that. May need some clarification though. Worth a shot?

3Dyan

Didn't do the trick. Wires are still crazy

Luka

you can always render out a UV template (ifits uvd already) and apply it as the diffuse

spacefrog

The wires getting slimmer towards the end is a limit with the standard material "wireframe" option
But that is not what your initial problem is

Your screenshot looks like you got some double faces or vertices on the one problematic part. Check your geometry on that lower part with the especially strange wire narrowing


If it's not some geo error, minimal sampling is the key factor here, as i have dealt with your exact problem too in the past. Mabe you got some other advanced MR settings wrong

I would recommend setting up a simple scene with you exact render settings and a teapot with your material applied which reproduces the problem and post the scenefile.
If you can't repro on a teapot, mind posting your problematic scene file?

3Dyan

Upping the sample rate did solve the issue of that wire missing a chunk from its middle, but the vanishing near the vertices still remains. I'm pretty sure it's related to the thinning, as you can see in the photo with the thick wires that some are much thinner than the others, and those are the problematic ones.
Upping the sample rate smoothed it out to a degree, but it's still an issue.

I tried it on a teapot and got this:


Pretty good, but still some areas with similar issues to the ones on my models.

My topo is ok, so that's not it, but here is the teapot scene (max 2012):
https://dl.dropboxusercontent.com/u/67063985/pot%20wires.max

Hope you can help me find what's wrong.

spacefrog

Those (almost invisible) issues in the teapot pic are indeed from the thinning of the wires. Again, this is a limit of the "Wireframe" mode of standard materials. You can't do anything to remove this.
But you initial issue shows disappearing wire regions in the middle of a wire, that is because of the undersampling. So when this is solved by upping the minimal sample rate, your initial problem is solved. But i really can't see the thinning problem towards the end being a big problem for your purpose. It only gets noticable when you dial up the wire thickness enough...

If you want correct wire texture, you have to use a explicit wire map plugin or something. Or maybe someone has written a specific MR wire shader, but i don't know of one out of my head

Blurbeta also has "WireTex", a map plugin, don't know wether this works for MR or not (look for it on maxplugins.de). Ghosttrails also has an Edgemap plugin (http://www.ghosttrails.net/otherplugs.html), same story, don't know weterh this works for MR

3Dyan

Thanks for the help.