The system variable *r4x_tangent* defines how far from tangent a corner can diverge and still be called tangent. This variable can be edited with the NCVAR command. The following picture illustrates what is measured to determine tangency.
When a tangent corner is found, the motion around the corner smoothly changes the angle of the head to bisect the angles that would represent the position perpendicular to the material. The following illustration shows the head position at the tangent corner as well as the positions that would have been perpendicular to the material to be cut. For clarity, this illustration exaggerates the corner appearance. In normal use, this corner would be much flatter than the illustration.