Select a point from the instance that will move and a point from the instance that will remain fixed. In addition to selecting a vertex or a midpoint, you can select a datum point, a reference point, or the origin of a datum coordinate system.
Abaqus/CAE moves the movable instance so that the selected points are coincident.
When Abaqus/CAE prompts you to select the point from the fixed instance, you can select a datum point or a reference point that was created in either the Part or Assembly module. In contrast, when you select the point from a movable part instance, you can only select a datum point or reference point that was created in the Part module.
If the coincident point constraint conflicts with existing constraints, Abaqus/CAE displays an error message and cancels the operation. To avoid the conflict, you can try reversing the selection of the instance that will move and the instance that will remain fixed. Alternatively, you can convert the existing constraints to an absolute position and reapply the coincident point constraint.
tool in the Assembly module toolbox. For a diagram of the tools in the Assembly toolbox, see Using the Assembly module toolbox.