Bug Report - FBX/OBJ import failing on simple quads


Importing “flat” geometry into roblox studio does not produce correct results. Models that end up with a size of 0 on any axis appear to always be broken/invisible.
This is easy to test with an .FBX or an .OBJ consisting of two triangles as a “quad”.

Source in 3dsMax:

Source as FBX (problem exists with OBJ too)
quad.FBX (9.5 KB)


Note that the mesh has a correct “size” of (8,0,8) but no visible geometry.

Reproduction steps:
(Reproduces 100% of the time)
Import the above .FBX file into studio.
Use either the “Custom avatar” importer plugin, or the asset manager importer.
Any mesh with a size of 0 on one axis will produce corrupted results.


Interesting, I can reproduce the issue with your file, but exporting a 2-triangle quad from blender works fine.


Interesting, I wonder if I can reexport through blender… I’ll try and report back.

Update: That works but the scale got mangled somewhere… Seems blender doesn’t support text FBX files, fwiw.


Yeah I was hoping to compare ASCII fbx outputs, but I can’t get it from blender.

I think there may be something up with our importer, thanks for reporting, we’ll take a deeper look


I’m going to bump this because
A) it’s still broken
B) I have new information!

It seems quads, when they do import (say with a tree with fins) also get incorrect tangent and binormals generated.

When I generate the mesh myself and pass in the tangent information via the roblox cloud API, the tangents are generated correctly.

Quad on the left is just a straight 0…1 uv’d quad from 3dsmax via the studio importer, quad on the right is procedurally generated.

This also appears here (and I’ve seen it myself in my own trees too).


I am a little bit new, can you tell me how did you create the quad?

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Did you tick “Double Sided”?

That may fix it.

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i ticked “Double Sided” and it didn’t fix it.


This appears to be fixed now. Thanks!

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