On the base of the constant removal rate of the metal material, the motion model of tangential point tracing grinding of Non-round parts should be given respectively according to type of the parts.

The quality of this transition is best visualized by a straight line drawn between two circles: the line's only point of contact with each circle is tangential.

Please pay attention to the subtle differences, particularly the Tangential line marking the fillet's point of contact with its adjacent surface, and how the reflections break there as well.