3D model mesh info

A header with your file name, the number of meshes and the number of materials. Then a line per mesh giving its name, vertex count, face count and material index. Then totals across all meshes, an axis-aligned bounding box printed as minimum and maximum coordinates to three decimal places, and a list of material names.

Whatever units the model itself uses, since nothing is rescaled. The numbers come from the raw vertex positions in the imported scene, so a model authored in millimetres reports millimetres and one authored in metres reports metres. Compare the extents against a dimension you know if you need to work out which.

No. The box is computed from mesh vertex positions as they are stored, without applying the scene graph transforms that position, rotate and scale each mesh. For a model whose meshes are already in world coordinates, which is common for STL and many OBJ exports, that is the same thing. For a rigged or instanced scene with transforms on its nodes, the box describes the mesh data rather than the assembled model.

No. It imports the model through assimp into an internal JSON scene, reads counts out of it, and gives you text. No file comes back, nothing is written, and your original is untouched. Use Convert 3D model when you want glTF or GLB output.

The same 40-odd that assimp imports: OBJ, STL, PLY, FBX, DAE, 3DS, glTF, GLB and the rest. This is the import side of the same engine Convert 3D model uses, which is the wide side. The extension has to match the real format, and a file assimp cannot parse is refused with "assimp could not read this as a 3D model" and its error code.

Because assimp parsed the file but the scene came back with no meshes. The OBJ and PLY readers in particular accept almost any text file and hand back an empty scene, reported as a success. Rather than print a report of zeroes, the tool says "assimp read the file but found no geometry in it".