Collinear
The Collinear constraint forces a pair of linear elements to become or remain collinear during the solve process. If other constraints on the part prevent the necessary adjustments to bring the pair together, the solve fails.
To assign Collinear constraints:
1. In the Generate Constraints dialog box, click the Assign radio button. Then pull down the Type selection list and select Collinear.
2. Click Apply.
3. Click each of the two linear elements to be constrained.
4. Click End or go on to the next constraint.
Each linear element in a collinear pair is labeled with the collinear icon,
Constraint Types, and a reference number that is unique to the pair.