[Solved] 3DCoat export / import into Unity problem

[Gian-Reto]

Hi

I am using 3D Coat since almost 2 Years now, so I have quite some experience with it by now. I used it with another engine last year without having import problems, but since I switched back to Unity (for other reasons) this year, I have more and more import problems with my meshes.
The way I use it normally is sculpt in voxels > Retopo > Pixel Paint > Export to obj > Import to unity

Most of them are connected to two Problems:
1) Smooth shading generating weird shading for long thin polygons in case these polys are not 100% flat (which happens often during retopo)
1) Smoothing Groups and the "calculate normals" creating ugly, visible seams along the edges (which does not happen with imported blender meshes as they don't need the smoothing groups ---> most probably thanks to the edge split)

Now, most of the time I could solve the problem by a) using the smoothing groups / calculating the normals in unity, which made the weird smooth shading issue go away with a mesh I imported some months ago.... but then the weird seam issue popped up, which I guess is just the normal way smoothing groups works (I guess the edge split IS superiour, at least for use with Unity, only less performant?)

Today I tried to fix a problem with another of my 3D Coat meshes where the normal map was baked wrong, by using additional polygons for some small details to help the normal map.

The same old weird smooth shading issue pooped up again, this time I could not fix it however.

I tried changing the UV seams, using smoothing groups or not in 3D Coat and on the Unity Import, tried obj, dae and fbx filetypes... I even thought that the triangulation on import might be the issue and did that once in the retopo room in 3D Coat. no luck!
See below for images about the problem:


1) This is the original Voxel sculpt

2) the retopo mesh

3) how it looks in the paint room (no problems with the shading visible)

4)And Finally after import into unity. One of the shading errors is marked in Red.

 

The weird thing is, I get the same shading errors in the 3D Coat paint room if I select "lock normals" when merging the retopo into the paint room. Might be some sort of clue what is causing these issues on import into other applications.

Now I am aware that I might reduce the errors by throwing additional polygons at my mesh and changing the UV mapping (there are also ugly seams all over the mesh, which I can't 100% map to the way the UV is layed out as similar problems are unknown to me with Blender Meshes)...

But before I do that I wanted to get some people with more expierience to look at the problem... maybe someone has seen something like this before and can tell me exactly why this happens? Or why I don't see similar problems in 3D Coat?


I guess it has to do with the Blender import and the way it triangulates the file.... it must treat it somehow different than blender files. But as I'm more of a programmer than a 3D Artist, I don't exactly know

Maybe someone that uses 3D Coat for sculpting, and imports this sculpts to Unity could lay out their pipeline and workflow so I can check if I do something stupid somewhere along the way?


Thanks in advance for any help!
 

[Gian-Reto]

this is really driving me nuts... I tried sculpting another object in 3D Coat to see if its just a problem with the other object, but lo and behold, the same ugly artefacts after import to another program. Seems like all I don in 3D Coat is messed up! See image...

 

this is really making 3D Coat almost unusable to me... if no one has any good idea, its Time to look into another sculpting option for me. This program has become a waste of time!

[Carlosan]

Hope it help

http://3d-coat.com/forum/index.php?showtopic=15232&hl=unity

[Gian-Reto]

Hmmmm, that might just be the Problem... I'll try it later today and let you know if that fixes the problem.

 

Thanks for the help anyway!

[Gian-Reto]

I just checked.... inverting the green channel solved the problem. Doh, I feel stupid now

 

Well, lesson learned for the future.... check the normal map channels first before posting.

 

 

Thanks a lot!

[Carlosan]

or just select "Unity" as Normalmap Software Preset when merging to paint room, and the normal map Green channel will automatically be flipped on export.