Hi Michael,

Just for the record have managed to record different examples of tangent behavior.

This example is from SolidEdge, it's the tangent circle creation mode.
It's basically a "2pts on edge circle" with a fixed tangent 1rst point, is has a live dragging of the circle.

http://www.youtube.com/watch?v=7Obe3PcQSVw


This one from Autocad, it is a "3pts on edge circle", in this example: tan, point, point.

The reference circle is in white and in the background there is a gray shape to show an example of tracing situation.
This behaves in a different way as the tangent point will change depending on the two points picked afterwards. The results does not show after the 3rd point has been set.

http://www.youtube.com/watch?v=mBDykzSGk88


I hope this is not too confusing.

Regards,

Marc