Best Answer
A useful Microsoft 3D Viewer alternative should do more than open a model file. For game, web, Unity, Roblox-style, Unreal, or product-viewer workflows, upload the GLB, GLTF, FBX, or OBJ, preview whether it loads, inspect scale, orientation, materials, textures, polygon weight, file size, source tool, target engine, and export format, then decide whether to optimize, convert, or send the asset into a playable prototype workflow.