Vertex Colour space is distorted by 3dsmax babylonjs glb/gltf exporter.

[RuneMod]

Regarding vertex colors, I believe there is a wrong or missing color conversion somewhere in the export process.

See image comparison of fbx and glb from babylonjs exporter.

[bghgary]

Can you provide a repro? This repo is currently no longer under development, but if anyone wants to try to fix it, we will still review PRs.

[FrogsInSpace]

After some research/investigation, i am 100% sure its not a babylon exporter problem
Internally Blender seems to use sRGB for vertex colors, and i guess the glb/gltf importer is missing the conversion step to convert from linear RGB (gltf ) to their sRGB space.

Also i verified that the color values written out by the babylon exporter are exactly the same as the values stored in the FBX

Here's a test using sketchfab upload of the 3ds Max exported fbx and glb ( by babylon) and sketchfab produces the exact same output for both

GLB (Babylon ) upload
https://sketchfab.com/3d-models/vtx-col-glb-babylon-exporter-9209df94313d40cba944838a991ee53f

FBX upload
https://sketchfab.com/3d-models/vtx-col-fbx-b7f8803b57764208b3c1c84d342d3b8a

regarding the blender sRGB usage for vertex colors, see here
https://blender.stackexchange.com/questions/87576/vertex-colors-loose-color-data/87583#87583

[RuneMod]

Interesting. Its hard to believe believe blender is at fault, but your explanation sounds very plausible.