The Collapse Tangent command allows you to create corners with XirusCAD. The tangent values at the selected point(s) will be set to 0.
You can call the Collapse Tangent command from the XirusCAD menu, from the XirusCAD Toolbar or from the command line. Select the points on your XirusCAD curve. The tangents of these points will be collapsed. This means that the tangent values at those points will be set to 0.
In the video, the Collapse Tangent command is found under a different XirusCAD menu item.