STEP (beta)

Solid B-rep for CAD interchange.

STEP exports a true solid (B-rep) rather than a mesh, for handoff to mechanical CAD. The parametric core — primitives, booleans, transforms, fillets/chamfers, hollow, and clearance — exports as editable analytic B-rep. Geometry with no analytic form (an imported raw mesh, or a moved edge/vertex) still exports, but as a faceted shell of many flat faces — usually a solid when the mesh is watertight; whatever cannot be closed into one is written as an open surface the export names — not an editable analytic surface. An optional "fit curved surfaces (beta)" toggle in the export menu rebuilds detected cylinders, cones, spheres, domes, tori, and partial surfaces like fillets and half-pipes in a mesh (holes, bosses, countersinks, balls, rounded tops, rings, rounded edges) as true analytic surfaces, falling back to facets where it can't. A second toggle, "keep flat facets" (on by default), exports a cylinder, cone, tube or sphere whose side count you SET, such as a hexagonal nut trap or a .scad sphere($fn=8), with the same flat faces as its STL; one left on Auto stays a true curved surface.

1. File → Export → STEP.
2. The scene exports, or only the parts you picked with "Selected parts only" — parametric solids as editable B-rep, meshes as faceted shells.
3. Open it in mechanical CAD.