Assemblies overview

Assemblies arrange parts into products. A part defines geometry; an instance places that part into an assembly. Multiple instances can reference the same part, so one part edit updates every occurrence.

Parts and instances

Use the bottom item strip or outliner to create and activate assemblies. Instances carry placement data, and the assembly solver can override placement when mates are present. Selection in assembly mode is distinct from part feature selection: you pick instance topology such as faces, edges, datum planes, datum axes, and datum points.

Mates

Mates express relationships between two instance references. Kerf supports rigid, planar, concentric, revolute, slider, distance, angle, parallel, perpendicular, tangent, cam, gear, rack-pinion, belt, and screw mate kinds in the IR. The UI starts mate creation from current assembly selections and exposes the inspector so side A and side B can be filled deliberately.

Sub-assemblies

An instance can reference either a leaf part or another assembly. Use sub-assemblies to keep repeated mechanisms, fixtures, or purchased modules together while placing the group into a larger design.

A practical pattern is to model and test the smallest moving group first, then place that group as a sub-assembly in the product. Keep part names, instance names, and mate names explicit; the outliner and assistant both use those names when describing what changed.