I have a CAD mesh that I exported from MOI3D, and when I bring it into Marmoset it seems to have no shading problems which is nice. My problem is when I import that mesh and re-export it out I'll get certain issues that wasn't present before.
The left is my re-exported version and the right is what directly came out of MOI3D. I used marmoset toolbag for this test. Both versions are only tris. These are from long thin tris, but I thought you wouldn't get issues on flat surfaces.
I also don't know re-exporting is giving me a different result. This is a concern because if someone reexports the mesh there will be shading problems.
Here are my two files, the MOI3D one and the reexported one.
https://www.dropbox.com/s/ck8ev7uqpz4f7dq/MOI3D.obj?dl=0https://www.dropbox.com/s/vrwp5ktlarrbyhk/Reexport.obj?dl=0I also tried to export the n-gon version and convert to tris then export it out then into marmoset, which has issues. I couldn't resolve it using any weighted normals or anything.
I'm a bit confused because I was always told you can use ngons on flat surfaces, but make them tris first and everything will work out perfect.
Is there some custom normal data I'm not aware of in the MOI3D version? I cannot see any difference when I reviewed the OBJ files.
I did notice that the OBJ for MOI3D has smoothing groups, but not the re-exported one. I did a test in Blender quickly, but not Maya yet. When I do export with smoothing groups it still gives the same issue sadly, and the exported one has different s # values.
https://www.dropbox.com/s/5tzyjt1147ymb26/rexportsmoothg.obj?dl=0I'll do my Maya check now and edit this post.
Maya seems fine
https://www.dropbox.com/s/gxj3212en0ereqa/mayaexport.obj?dl=0I'm worried that this mesh could give off mixed results depending on where it goes. Or is there something with the normals I need to correct?
Toolbag 4 and Viewer files
https://www.dropbox.com/s/c0q9wib6o0tsola/ToolbagScene.tbscene?dl=0 (Toolbag 4)
https://www.dropbox.com/s/joih9fcnkxec6z9/Viewer.mview?dl=0
Replies
https://www.dropbox.com/s/c0q9wib6o0tsola/ToolbagScene.tbscene?dl=0 (Toolbag 4)
https://www.dropbox.com/s/joih9fcnkxec6z9/Viewer.mview?dl=0
If I remove custom split normals data it will show like this
Then if I average the normals
Something has to be causing the normals to get messed up on export. The problem is I cannot be sure someone wont take my MOI3D export and re-export it then they will have these problems as well.
I'm guessing you are modifying the normals in some way with import or export settings, or having unlocked normals or maybe allowing Maya to use it's custom normal settings which is on by default, which would bork normals.
I tried using Eevee to just check the MOI3D on import
If I clear custom split normals
It fixes that part, but then introduces new problems.
But if I was polymodel this same piece would I also get those errors due to the tris on the flat surface? Is there something I'm missing? I don't recall having any issues with ngons on a flat surface once converted to tris before.
This is really confusing. I even did a few tests with a rectangle and cuts on a flat surface and even converting to tris has these long thin tris, but no shading issues. If I slightly change the shape to make the surface not flat it introduces such problems, but I think the above is an issue related to mesh normals, but I cannot track it.
This causes visible edges like you have - because you have two edges right next to each other. Or even overlapping. This is not uncommon with N-gons - which is why people say to avoid them.
You need to edit the mesh to get rid of the long, thin, and closely spaced, triangles.
Obviously you can see where the bad triangulation is but you can also use the cleanup tool in Maya to check for this. (Mesh>Cleanup)
this is an exaggerated example of what I think you'll see if you zoom in on the closely spaced edges
I'll run it through a mesh clean up just as a test, but yes I could also redirect it better by just exporting the ngon version from MOI3D and then doing some manual work. It just becomes a lot of work when dealing with any boolean cuts as I have so many vertices to manage
I'll post back when I've finished.
Thank you!
Example file
https://www.dropbox.com/s/u2xnvarn1bvzkfy/ngonversion.obj?dl=0
MOI3D is a real life saver for CAD models!
Thank you!