The Symmetry Constraint centers two selected points to be symmetrical around a given line, i.e., both selected points are constrained to lie on a normal to the line through both points and are constrained to be equidistant from the line. Alternatively it can constrain two points to be symmetric with respect to a third point.
You can only use it with tree points or two points and a line. Symmetry button has an two important advantages. First one, It centers to drawings in 2D sketch. Second one is it helps to use less constraint like center, point and dimension.
If you want to understand better how to use it, You should watch my video below. Also I add technical drawing of video to practice with it.
If I tell you how symmetry button works shortly. Firstly draw a line or geometric shape. Then follow steps below. There are two working principle of this constraint button.
- Click the symmetry button first: select the first point, then the symmetry reference point, and finally the second point.
- Click the symmetry button last: select the first point, then the second point, and finally the symmetry reference point.
