Can't bake normals without seams along polygon edges

TH98

I've been having this problem for like a year now, and I've not seen anyone else who does. When I go to bake a normal map on an organic shape, it'll end up with harsh seams along certain polygon edges, like this:


There's only one smoothing group on the mesh, and there aren't any disconnected verts--the lowpoly looks pretty much fine:


Filtering the normal map seems to reveal the seams:


Right now I'm baking in Xnormal, using an SBM exported from 3DS Max as my lowpoly. In the past, though, I've baked normals directly in 3DS Max and had the same problem. What's the deal here?

Ben Apuna

Before you bake, do you move the mirrored UVs outside of 0-1 space so that they don't overlap the other side?

TH98

Yes, but I get this same problem on models that have no UV mirroring at all, so I don't think that's it.

ZacD

what app are you baking in, what 3d app are you using?

Ben Apuna

You are aware of the whole Max "normal maps not synced to viewport" issue, yes? It might be that maps baked in xNormal will not work right in the Max viewport.

What are you using to preview your models with normal maps applied?

Have you tried the 3PointShader?

I read there was a recent hotfix for Max to sort this issue out somewhere on the forum.

PhattyEwok

yeah the new Service Pack for max takes care of the normal issues so head on over to Autodesk and dl and install. If you are still having problems with the bakes at least you'll know it isn't a problem with max's viewports....

-edit-
upon further look at the normals it looks a little bit more than just max's viewports. Are your normals baked out at 8 or 16 bit?

EarthQuake

This looks like an issue with unwelded UVs, me personally I have issues when exporting from modo to maya/max, I have to do a simple weld as I get randomly unwelded UVs from modo, so maybe look into that.

TH98

EarthQuake wrote: »

This looks like an issue with unwelded UVs, me personally I have issues when exporting from modo to maya/max, I have to do a simple weld as I get randomly unwelded UVs from modo, so maybe look into that.

Well, for what it's worth, here's the UV at the time of exporting:


Switched to a different model to get rid of the symmetry factor which was giving me some separate issues. This one has the same sort of seams, though:

TH98

ZacD wrote: »

what app are you baking in, what 3d app are you using?

I'm exporting the lowpoly from 3ds Max, then baking in xNormal.

Ben Apuna wrote: »

You are aware of the whole Max "normal maps not synced to viewport" issue, yes? It might be that maps baked in xNormal will not work right in the Max viewport.

What are you using to preview your models with normal maps applied?

I'm rendering the normals in Cinema 4D. The seams also show up on the models when they're ported to the Source engine as well, so I don't think it's a display issue.

PhattyEwok wrote: »

upon further look at the normals it looks a little bit more than just max's viewports. Are your normals baked out at 8 or 16 bit?

tbh I'm not sure what that means. Here's all my xNormal settings:

PhattyEwok

Well I don't have much experience with xnormal but I know in Max or Mudbox when you bake normal maps out at 8-bit you can get normal distortion the way those errors are faceted though suggests something else though...

I'm really at a lost to what is happening are you sure that your model doesn't have any un-welded vertices? Perhaps some vets can chime in?

Also could you post your high and low and I can see if the normals bake out correctly on this end.

TH98

Here's a zip, low in .max and high in .obj:
http://dl.dropbox.com/u/3677532/normalseams/joe.zip

PhattyEwok

SO had a look at the files and baked out a couple tests. Your low poly still had a couple modifiers in the stack. Generally I collapse the stack before baking out. After I did that the normals baked just fine.

Here's a screen grab with 3-point shader


Also a zip with two normal map sizes and the screen grab...
http://dl.dropbox.com/u/3911509/Joe%20Normals.zip

I think collapsing the stack before you bake should solve the problem. I also baked these out in Max vs xNormal with a projection cage so that could be a variable too. As well update your video drivers if you are still having problems. Sometimes just doing that can magically make the problems go away

TH98

Interesting, I'm still getting the seams problem in Cinema 4D. And it's actually looking pretty good in Source.

I guess it was a C4D problem all along. Boy is my face red. Thanks a ton for the help guys

EarthQuake

I dont imagine C4D has a very robust baking/normal preview workflow, so that would explain it.

PhattyEwok

TH98 wrote: »

Interesting, I'm still getting the seams problem in Cinema 4D. And it's actually looking pretty good in Source.

I guess it was a C4D problem all along. Boy is my face red. Thanks a ton for the help guys

No problem that's what polycounts for:)