Vertex paint Blender to Painter issue + edge small anomaly

[Mark - Da_Drood]

Hi everyone, i'm here asking for you help to sort this issue and to understand whether i'm facing a bug or i might doing something wrong.
I have a couple of assets with vertex paint i want to import into Painter. In the photos down here i'm showing the vertex paint done in Blender, and the result after baking the ID map (with vertex colors option). I've done id map baking previously already and never faced any issues until now. Plus, as you can see from the red circled areas, there are edges across a couple of faces which are not present in Blender.
So beside the edges issus, which is no big deal, i would like to understand what's the issue with the ID map baking. Why does Painter dislikes my windows?? What did they do wrong to it? ;/
Thanks in advance to whoever will be a patient soul and will be able to help.
Hopefully it's easy to fix.

[Cyril Dellenbach]

Hi @Mark - Da_Drood,

Thanks for the screenshots, I am pretty sure your windows didn’t do anything wrong, but maybe they are keeping secrets from us.

First of all, Substance 3D Painter always triangulate your assets in the backroom while importing a mesh, therefore you may see one of your quad triangulate, but nothing to worry about (you can always check there is no overlapping vertices or triangulate your mesh yourself before importing).

And for the ID map, this is difficult for me to give you a proper help without more information about your baking parameters, but I would check that the mesh is correctly in its cage (Frontal distance/Rear distance). Would you mind sharing with me your mesh so I can dig into the problem? 

In the meantime, you’ll probably be able to mask the parts where the ID map doesn’t work with the Polygon Fill tool (give a try to the mesh fill or UV chunk fill option).

Have a nice day,

[Mark - Da_Drood]

Hey Cyril! Thanks so much. I sent you a private message with the links to the files 🙂

[Cyril Dellenbach]

Hi again Mark,

We have found the solution of the issue. The .fbx format being owned by Autodesk it seems blender can have some issue while exporting to this format (especially with the vertex color). If you really need to keep your assets in .fbx, this thread may interest you.

With that being said, we tried to export your assets in .gltf (which also contains vertex color information) and this worked perfectly with Substance 3D Painter. BUT (it would have been to easy) since the 3.4 version of Blender, the vertex color is also messed up with .gltf. Therefore, I suggest you to use the Blender long term service to avoid this kind of problem.

Best regards,