Select Constraint
Coincident Point from the main menu bar to apply a constraint that positions a movable part instance so that a selected point is coincident with a selected point of a fixed part instance. All position constraints are features of the assembly and can be suppressed or deleted using the Feature Manipulation toolset.
To constrain two part instances with coincident points:
From the main menu, select ConstraintCoincident Point.
Tip:
You can also apply the coincident point constraint using the 
tool in the Assembly module toolbox. For a diagram of the tools in the Assembly toolbox, see “Using the Assembly module toolbox,” Section 13.8.
ABAQUS/CAE displays prompts in the prompt area to guide you through the procedure.
Select a point from the part instance that will move and a point from the part 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 part instance so that the selected points are coincident.
When ABAQUS/CAE prompts you to select the point from the fixed part 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 the 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 part instance that will move and the part instance that will remain fixed. Alternatively, you can convert the existing constraints to an absolute position and reapply the coincident point constraint.
