ZBrushCentral

Zbrush / Marmoset display normal issue

ZBrush Usage Questions
#1

I have been working on a head model and im having real trouble with normals displaying in Marmoset but I feel its an underlying ZBrush issue.

Sculpt in Zbrush.

I export its low sub div.

Bring this into Marmoset and it displays like this…

If I take this model into Max, reset xform, edit normals, unify and reset etc… this does not fix it. If I export as an fbx, bring back into Max, xform, normals, smooth… that does fix the problem. I can bring this mesh into Marmoset and it displays normally.

However, if I bring this new fixed mesh back into Zbrush as my replaced low sub div level… and then export the same mesh out of ZBrush, I am back to square 1 and the problems back.

Exporting say sub div 3 gets this result…

Its still screwed but you are only getting the screwed poly lines from the lowest sub div level… weird!

I have tried using Maya to export my mesh but that doesnt get me anywhere.

Its like I can fix my mesh outside of Zbrush and then import it into Marmoset but any time I go back into Zbrush my newly fixed mesh gets unfixed.

As I want to export my higher sub div levels for baking in xnormal… I need to some how fix the underlying problem and succeed in exporting meshes from ZBrush in a fixed state.

Does anyone have any idea how to fix this? Ive spent far far too long on this mesh to abandon now. I need to fix this. Any normals I bake from any exported mesh from ZBrush have this sub div level one screw up.

Many Thanks

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#2

An additional problem i’ve found is that supposedly cleaned up meshes exported from Maya, when brought into xnormal for baking revert to having the same problem.

Its almost like they appear fixed but underneath are not.

#3

I have solved this now, luckily )

#4

Well, how? Others reading this thread might be interested…

#5

Fair point.

I’m not sure why but if I reuved the lowest sub div in Maya, didn’t work in Max or Zbrush itself but Maya… Then bring that back into Zbrush. Exported higher sub divs were fixed shrug

No idea :slight_smile:

#6

Many thanks.

In case it’s of interest, ZBrush doesn’t export normals if you export as OBJ. I don’t know offhand if GoZ to Maya or Max includes them. If not, those programs would calculate normals on import, based on the vertex order.

However, you can export normals from ZBrush (either hard or smoothed) using the FBX plugin.

HTH,

#7

It’s a recurring problem if you do your UVs in Max… Max have an annoying tendency of not been a good team player!

The issues, is that it deal in a strange way with the export of the UV in any format (obj ,FBX and goz included). If you look to your UVs they look OK but sometime every polygons of your UV unwrap are separated (not weld at export time AND only at export time…) creating artefact in the calculation of the normal difference between the high def model and the low def one or in the displacement map calculation.
the solution… be extra careful when you use goz on zbrush models with UVs.
In the last update to Maya this is happening too!

Now come the hard part: This is happening at random. Some time your export will be good and once in a will your export will screw your models UVs!

In production for us it became a nightmare. We stop relaying in exporting from MaYax (max and may the same)! It force us to work with uvlayout… which it already what we were doing anyway, but we lose in flexibility doing the unwarp in the last stage of the modeling process… no unwarping before the model is totally finish in zbrush.

#8

Hm, I’m seeing that separated polygon problem when reimporting it in Max, yeah. Tools that weren’t using GoZ. I exported regular objs, UVed them in Max,. or 3D-Coat, then Max. They seem fine in Max the first time, but when I re-import them back in Max for any reason, then the polygon’s are separated.

Another issue I’m having now in P2, loading up a tool from the first 4R7 release, the UVs of the tool are slightly altered. They appear mostly fine, but slightly thinned and warped, as if they’ve been smoothed. You’ll see the difference if you export a texture and place it on the old one. Or, like I need for one subtool, if you bring in your diffuse and try and bake it down on the model to work further on it. It’s warped.

This is a real problem right now…

Edit: Well, one tool is working fine. The one that had the UV issue was a tool where one of the subtools was in HD geometry (but not the subtool that had the UV problem). It was saved as a test in the 32 bit 4R7 (since the 64 bit version couldn’t do HD at the time) from a 4R6 file. Perhaps it’s still something lingering in the pre P2 versions trying to convert things that carried over.

I don’t know. But resaving that old 4R6 tool into the new 4R7 P2 64 bit version shows no issues with any UVs on that one. So, anyway, I guess I just suggest that you check your UVs on subtools to see if they’re retained properly.

#9

Further testing. Looks like this has the potential to happen to any tool. The reason seems to be if you go back down to the first subdivision level, then back up again for any reason, it’s applying a smoothing to the uvs and recalculating the final polygons again. The model will look unchanged, but if you baked off a texture, apply it again and you might find it’s warping.

I notice that, even though the subtools never had this pressed in 4R6, by default they’re coming in with the SUV (smooth uvs) button on in the Geometry subdivision tab. I think it’s applying the UV smoothing whether you disable this button, or not.

I also notice that, even if you have a mesh partially hidden, when you go back up in subdivisions the message up top says it’s subdividing the entire final polygon count of your mesh. That doesn’t make sense to me. I’m going to make a support ticket for this, but I want to make sure people here are warned about the problem, too. It’s not something immediately apparent. Maybe it’s just on my end, but I doubt it.

The kicker that this is a 4R7 issue: I have no issues with these tools in 4R6 doing the exact same things. It’s unfortunate, but until this is solved I can’t use 4R7. I can’t trust it for maintaining the 1-to-1 ratio of my UVs. I’ll stick with 4R6 until this is fixed and verified as stable.

#10

Wow! Indeed you right, this one is a big bug. Hope they fix it soon.