[Q] Materials dont get along mesh with seperation

Im having this issue when i seperate a part of a mesh of a excisting mesh the material dont get along. Im getting empty material on the mesh. Is this normal behavior


this is not normal. send us the blend file for review, or give us a step by step guide to recreate the problem.

Well i should have tested this also with other engines. Im using a different renderer than Cycles or BI. Its Thea Render, when i do the same with either one of them it works just fine. So its related to that renderer and i should contact the dev.

Sorry for that, ill will set this to solved.

Well its actually doing the same. If i start a from scratch it works fine. When i do it with the scene where i noticed it, it also happens in BI.

Here’s a small part of that scene

Attachments

Seperate-Mesh-Material_Error.blend (211 KB)

I think i see the difference. When i look at the outliner and see the structure there. The materials are listed under the mesh data. Where in the other model the materials are listed under the object data.

This comes in from FBX, but i did not know that there can be a structural difference on how materials are linked to model. Is this actually normal then?

Attachments


Solution now is, delete materials and add them again.

I actually used the Alembic importer, so i need to report this i guess. Seems like a bug.
Ive tried to export a mesh with 2 materials as alembic, then import it again. It show exactly what i noticed. Materials dont get imported under mesh data but under object data.

Made a bug report here, hope its in the correct spot there.

materials that come with FBX files are not always compatable with other programs, as they may be created in a complicated way in its original program. for instance, if you make a blender material in the node editor and export it to any other 3D program it wont be compatable. Color information will remain, but i believe that is about it.

however i still dont see why it wipes the material when separating a part of the mesh, never seen anything like it.
however since its an imported model, first thing i would do is wipe it, remove any object data, materials, or equivalent. that did solve the issue as you also pointed out.

Well it was actually a alembic model. FBX importer does it correct way, material are under mesh data. Alembic import shows material under object data

Seems it was a ‘bug’, it got fixed know.
https://developer.blender.org/T50757

amazing to see how they actually listened so such a minor thing… great!