Same Distance
Samedist is assigned to two pairs of elements. All geometric elements except for spline-based entities (rational splines, bsplines, and ellipses) are eligible. You can assign constraints to the interpolation or control points of these entities, just not the spline itself. Samedist forces the distance between the members of the first pair of elements to be the same as the distance between the members of the second pair. If other constraints prevent the two distances from being made equal, Solve fails.
To assign Samedist constraints:
1. Click Parametric and then, in the Create group, click 
Constraints.
Constraints.The Generate Constraints dialog box opens.
2. In the Action area, click Assign.
3. In the Type box, select Samedist.
4. Click Apply.
5. Click the two elements for the first pair.
6. Click the two elements for the second pair.
7. Click 
OK or assign the next constraint.
OK or assign the next constraint.Each element in a same-distance set is labeled with the same-distance icon, , and a reference number that is unique to the set.