Assemblies & mates
Insert parts into an assembly, position them with mates, then check interference, explode and count a BOM.
An assembly places parts (components) together and holds them with mates — rules like "these two faces touch" that keep positions correct as parts change.
Building one
- New Assembly from the tab strip (or ask the AI).
- Insert Component — pick any open part tab (or a saved file). The first component lands fixed ; everything else mates to it.
- Move / Rotate drags free components; mated ones only move within their remaining freedom.
Mates
Pick two faces/edges/planes, then the mate type:
- Coincident — faces touch, flush
- Concentric — cylinders share an axis (pins, shafts, holes)
- Distance / Angle — held apart at a value you can edit later
- Parallel / Perpendicular / Tangent — orientation control
A part starts with 6 degrees of freedom; each mate removes some. Fully mated parts can't drag at all — under-mated ones can, which is often what you want (hinges rotate!).
Checking the design
- Interference check — finds every pair of overlapping components and reports the intruding volume.
- Exploded view — pull components apart along axes for documentation.
- BOM — the live parts list with quantities; it lands on drawings too (2D drawings).
Configurations in assemblies
Each component can use any of its part's Configurations & design tables — one assembly can show the long and short variants of the same bracket side by side.
When it fails
- A mate turns red — it conflicts with earlier mates (e.g. two distances that can't both hold). Delete or edit one; the tree lists every mate under its components.
- A component jumps on mating — both solutions satisfied the mate; add an orientation mate (Parallel) to pick the side you meant.
Related: Configurations & design tables · 2D drawings · Your first part (sketch → extrude)