I’ve been trying to get the facet normals to work on a glb, however they always seem to be not in the correct position (maybe flipped?).
Expected:
Result:
Same happens when for example, exporting the icosphere from the first example as glb (from the debugger tools), then importing and applying the same code, the normals are not correct:
There is some transformation for left-handed system which I believe should be taken into account when comparing.
You may try scene.useRightHandedSystem = true to check.
I tried the righthanded system to true, but it didn’t change the normals issue. One solution is as above (use world position and world-negated normals). I wonder why is negating normals necessary?