is there any way of preventing godot splitting vertices on mesh import?

punyrobot

hello! i'm trying to make a soccer goal net, with the goal of doing a simple cloth sim using MeshDataTool, but when i export my mesh from maya the vertices at places like the corners are split - that is duplicated , so i lose the connectivity information i need. so my mesh in maya has 51 verts, but the godot import has 56. maya mesh has 104 edges, godot has 116. The Net (hah) result being the mesh tears itself apart.

i've tried exporting as obj, dae, fbx but the behavior is the same in all cases. i've also tried ensuring that there's single mesh data per vertex - uv's color values etc.

(i've tried using a physics softbody, but that doesn't seem to catch collisions at all, or at least not reliably) thanks for any insight!

punyrobot

sorry maya mesh (and obj) has 41 verts, godot mesh 56

Megalomaniak

Do you have any smoothing groups on there perchance?

punyrobot

not that i'm aware of! i'll check that

punyrobot

aha , not smoothing groups, but there were multiple normals per vertex which seem to cause the problem, thanks Megalomaniak!

punyrobot

it appears that having more than one uv per vertex also causes the splitting

Megalomaniak

Yes, split normals and UV seams need extra vertices to store that info. This isn't an issue with godot but a technicality of graphics in general.

punyrobot

well, it's a choice no?, you can store multiple normals or uvs on a single vertex instead, that's how maya does it internally.

TwistedTwigleg

Possibly, but Maya could also be using a different internal format that is more suitable for 3D creation rather than rendering. Probably when rendering in Maya it splits the vertices and passes the info to the renderer. From my very limited OpenGL experience, I think you can pass more information per vertex but it adds up quickly in VRAM, as you have to define the structure of the vertex info ahead of time and every vertex will allocate that amount of memory regardless of whether it uses every field/attribute.

Megalomaniak

Yes theres certainly more to it but consider that unlike game engines DCC applications like maya don't need to be as concerned with performance and memory usage.