support-fins

Add breakaway support fins to an STL, baked into the mesh. Tip a part into its strong orientation, run this, and print without slicer supports.

uvx support-fins part.stl                 # writes part_fins.stl
uvx support-fins part.stl -o out.stl --gap 0.25 --thickness 1.0
uvx support-fins part.stl --fins-only     # just the fins, to import as a separate body

The part is used in the orientation it ships in and dropped onto the bed (z=0). Every overhang steeper than --overhang-deg with clear air to the bed gets a fin: a flared, chamfered foot, a thin wall, and a necked tip that stops --gap below the part so it snaps off. Overhangs above other parts of the model are skipped. Run --help for all dimensions (mm).

Python API

import trimesh
from support_fins import generate_fins, FinParams

res = generate_fins(trimesh.load("part.stl"), FinParams(gap=0.25))
res.mesh.export("part_fins.stl")

Credit

The fin algorithm is ported from prototype/spike_fins.py in gittrahan/support-fins (MIT), the engine behind printfins.com.