Parallel
The Parallel constraint is assigned to pairs of linear elements. A pair of parallel-constrained elements will be adjusted to be parallel at solve time. If other constraints on the part prevent the pair from being made parallel, the solve fails. The positions, lengths, and absolute slopes of parallel elements are not affected by this constraint and may or may not change during the solve, but the slopes of the lines will be the same.
To assign Parallel 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 Parallel.
4. Click Apply.
5. Click the linear elements to be constrained.
6. Click 
OK or assign the next constraint.
OK or assign the next constraint.Each linear element in a parallel pair is labeled with the parallel icon, , and a reference number that is unique to the pair.