3D Printing Files

File Formats

STL[1]

STL is this old format that uses only triangle to describe a 3D object. It's old and arcane but it is the most widely used format, it seems.

BREP[2]

BREP (boundary representation) is a CAD format that is actually standardized, unlike STL (as far as I can tell). But the files are absolutely huge in comparison (~20x bigger than an STL). Easier to iterate on because instead of just plastering triangles on everything, it actually describes shapes.

3MF[3]

3MF is another format for CAD that is broken up in to discrete files for different data, beyond the 3D object.

Conversion

I have been using build123d for my super basic conversions from STL to BREP so far. Tends to work but crawls when STL's end up over 1.5MB or so. I have also used Blender (software) to "decimate" the STL's, which is an almost linear scaling of detail to size (e.g. reduction from 1.0 to 0.25 in detail results in ~25% of the size).

References

1. https://en.wikipedia.org/wiki/STL_(file_format)
2. https://en.wikipedia.org/wiki/Boundary_representation
3. https://en.wikipedia.org/wiki/3D_Manufacturing_Format

Last modified: 202609021520