The software uses constraints to control how part symbol ports relate to each other and to reference ports. There are four constraints that can be defined by themselves or in conjunction with another constraint.
Parallel
Restricts geometries so that they are parallel. The constraint can only be applied between geometries with an associated direction. For ports, these geometries are axes and planes. A plane's direction is defined by its normal vector.
Perpendicular
Restricts geometries so that they are perpendicular. The constraint can only be applied between geometries with an associated direction. For ports, these geometries are axes and planes. A plane's direction is defined by its normal vector.
Coincident
Makes two geometries identical. Coincident constraints are only valid if one geometry can be made to touch everywhere with the other geometry.
Distance
Defines the minimum separation in three dimensions between two geometries. Unlike the other three constraints, this constraint has an associated value. A distance constraint can have different meanings depending on the geometry types and any other applied constraints.
As an example of constraints, consider this beam clamp and beam.
Two constraints allow the beam clamp to stay flush with the face of the beam while still allowing it to slide along the axis of the beam. The first constraint is parallel between the Beam XY-plane and the Beam Clamp XY-plane. The second constraint is coincident between the Beam X-axis and the Beam Clamp X-axis.