STEP import
Bring a STEP file in as a solid body — reference it, mate to it, and model on top of it.
STEP (.step / .stp) is the neutral exchange format every CAD system speaks. Use it for supplier models, customer geometry, or parts made in other tools.
Importing
- Import STEP (top bar) and pick the file.
- The geometry lands as an Import feature at the top of the tree — a real B-rep body, not a mesh: faces are true planes/cylinders/splines you can snap to.
What you can do with it
- Model on top — sketch on its flat faces, Extrude (boss & cut) bosses and cuts against it, Fillet & chamfer its edges.
- Reference it — measure it, convert its edges into sketches (Convert entities).
- Mate it — imported parts work in assemblies like any other.
- Modify it — no feature history arrives with the file, so reshaping uses direct-editing tools: Delete Face, Move Face, booleans and surface repairs (Surface modeling).
Assemblies
A STEP that carries an assembly structure is detected automatically, and the import dialog offers Import as assembly. That opens a new assembly tab with the real product tree: one part per unique product, component names, per-component colours, and nested sub-assemblies preserved — a sub-assembly used five times is stored once and referenced five times. Every component arrives grounded, because the file already positions them; use Float all if you want to mate instead.
Untick the option to get the old behaviour: everything as bodies in the current part.
Recognising features
An imported body has no feature history — but Recognize features (on the import's property panel) can rebuild part of one. Today it finds holes: through, blind, counterbore and countersink, matched against fastener standards so you get M6 clearance, normal fit rather than Ø6.6. The result opens in a new tab; your import is never modified.
Every recognised feature is verified by rebuilding it and comparing the result against the original solid — volume, area, centre of mass and a point-by-point surface check. Anything that does not match to 0.1 µm is refused and reported, so a recognised hole is a hole you can safely edit.
What to expect
- No history in the file — the source system's feature tree cannot travel through STEP; you get the final shape, plus whatever Recognize can rebuild from it.
When it fails
- Faces missing or a body won't shell — the file carried gaps; knit and fill the surfaces (Surface modeling), then thicken back to a solid.
Related: Import a DXF profile · Saving, opening & exporting