A few things worth knowing
Which input and output formats are supported?
Supported triangle geometry from STL, OBJ, PLY, uncompressed static GLB/glTF 2.0, plain OFF, 3DS and legacy VTK POLYDATA can be exported as binary STL, ASCII STL, geometry-only OBJ, ASCII PLY or plain OFF. Existing viewer parser restrictions apply. Select local BIN companions with glTF. Point clouds, lines and mixed primitive models are rejected. This does not support every variant of those formats or all 3D file types.
Does conversion preserve materials or animation?
No. Output preserves static triangle positions, triangle order and face winding, flattened into one mesh. Materials, textures, UVs, colors, hierarchy, original indexing, solid grouping, headers and original normals are not preserved. STL normals are recalculated. Unsupported source features and triangulation approximations remain subject to the parser notes.
What does sharing identical vertices do?
OBJ, PLY and OFF use indexed vertices. When sharing is enabled, positions that are exactly equal after source parsing use one index. This can connect formerly separate touching surfaces, so it is not a topology-preserving guarantee. Uncheck to write separate vertices for each triangle. No tolerance welding or repair is performed. STL stores triangles without a shared vertex table.
Can numbers or units change?
Binary STL rounds vertex coordinates to float32. ASCII files preserve parsed JavaScript Number values, but source parsers may already reduce precision. OBJ/OFF preview loaders additionally use float32 positions; preview-only differences are reported separately from serialized-file changes. PLY exports use double coordinate properties. No physical unit conversion is performed. glTF source coordinates use metres; these output files do not carry a physical unit declaration.
What limits apply, and is the output verified?
20 MiB per file, 40 MiB total, 100,000 triangles, 20 MiB output, bounded workers and previews. Coordinates must be finite and within ±1e12. Generated files are parsed again and geometry checked before the actual output preview and downloads become ready. WebGL 2 is required. This is not mesh repair or printability certification.
