Bringing parts together — mates, joints, degrees of freedom, and the assembly workflow.
Interactive 3D Model: Hinge Joint — two plates connected by interleaving knuckles and a pin, demonstrating a revolute joint.
An assembly is a collection of parts positioned relative to each other using constraints (also called "mates" or "joints"). This is where your robot comes together digitally.
A free body in 3D space has 6 degrees of freedom: translation along X, Y, Z and rotation around X, Y, Z. Constraints remove DOF to hold parts in the correct relationship.
Two faces or points share the same location. Removes translation DOF perpendicular to the face.
Two cylindrical faces share an axis. Leaves rotation around and translation along the axis.
Maintains a fixed gap between faces. Like coincident but with a specified separation.
Forces faces or edges to stay parallel or at right angles to each other.
A hinge. One part rotates around a fixed axis. Used for: arm joints, flippers, lids.
A slider. One part moves along a straight line. Used for: linear actuators, drawer slides, elevators.
Combines rotation and sliding along the same axis. Used for: lead screws, telescoping mechanisms.
Parts are locked together. Used for: bolted connections, welded frames, glued assemblies.