What is wrong with AI 3D models
Image-to-3D tools are made to look good in a viewer, not to run in a game. A prop that should be a few thousand triangles comes out at two or three hundred thousand. The mesh is often a soup of loose triangles that do not share their corners, so the file is three times bigger than it needs to be and the shading shows hard seams. Bits of noise float around the model. The pivot sits wherever the tool left it, so the model hangs in the air or sinks into the floor when you drop it in a scene. The size is anything from a centimetre-scale giant to a tiny toy, some tools stand models on the Z axis, and the textures are 2K or 4K PNGs.
What this tool does
Weld. Corners that sit on the same spot are joined, so the mesh becomes one connected surface. Reduce. The triangle count is cut with meshoptimizer, the same library many engines and glTF tools use. It only removes vertices, so UVs, vertex colours and skinning stay correct, and it keeps the outline of the model. Clean. Small disconnected pieces are dropped. Stand it up. Z up or X up is turned to Y up, the way Godot, Unity and three.js expect. Scale. Set a real height in metres, or turn centimetres into metres. A 1.8 m person stands next to the model so you can see it. Pivot. The origin goes to the bottom centre, so the model stands on the ground when you place it. Textures. Big textures are shrunk and colour maps are saved as JPEG, which is often the biggest saving of all.
Export
You get one GLB with the fixes baked in, plus a short report of what changed. With Pro you also get a level-of-detail set: the full result, half and a fifth of its triangles, named for an engine LOD group.
Is my model uploaded?
No. Everything happens in your browser. The sample is a deliberately messy model made in code: too many triangles, floating bits, centimetre scale, Z up and a 2K texture.