Lighting 3D Objects for AR

Discussion
1

I am creating an AR “app” for my local EAA chapter and their Young Eagles program. By scanning different QR codes and then a common “target”, a different historical aircraft displays; taping it starts a short narration. You can also use finger to rotate it and finger-thumb pinch to resize it.

My problem is three of the four aircraft (U2, SR71, B52) appear black, there is no source light applied to them. I converted the .obj files in Blender to .glb. They looked fine in Blender, textures and lighting appear normal. Only the BellX1, which I downloaded as a .glb from the Smithsonian is properly lighted.

Applying lighting modes in webAR has no effect. What I am missing?

2

Can you drag the bellx1 and the non-lit .glb into a reply here?
Perhaps we can examine them in blender and/or gltf-report and see if we can spot why they behave differently…

(You could first try just dragging them onto gltf-report and see how they look there, and examine the node hierarchy to see if one model has lights and the other does not, or if perhaps the working model has an environment map present in the file etc. )