Top three spheres on the left should be white, not gray.
Two large spheres on the left just below the three should also be white.
Model exported from 3ds Max 2018.4 using Max2Babylon 1.3.33
IBL is the Doge courtyard, processed via IBLBaker to create the blurred MIPs for environment lighting. I used this to compare the Sandbox environment lighting with the one used in the Khronos WebGL Reference Viewer. (http://gltf.ux3d.io/)
Top to bottom:
- Sandbox with Doge IBL.
- Same, but with the Base Color texture boosted to Level 2. This seems closer to the expected brightness.
- Khronos WebGL Reference Viewer:
I don’t have permissions to upload the GLB nor IBL. But this should be fairly easily reproducible.