Tan from curve command is not such when made (Rhino 5)

Rhino Rhino for Windows
1

Hi,
V5
I apply the line tangent from curve command by selecting the tool for that, select the large circle and draw line to small one (end of it) and no way is that line tan from the large circle.

I repeat it several times and it fails to be tan from large circle.

I copy it out to a new file, try left side and all ok, then delete rhs and try again, now it behaves, but at second look its not, it wont now snap to the end of the smaller circle, it wants to go tan to that, yet I didnt select the line tan from and to curve command.
TAN FROM CURVE IS NOT.3dm (28.8 KB)

TAN FROM CURVE IS NOT then is but wrong on small curve.3dm (29.1 KB)

Why ?
Steve

2

Hello- use Line > Tangent > 2Curves.
Or Line > Tangent and the Tan osnap for the far end.

-Pascal

3

Hi Steve,

I can’t repeat your first error.
I can’t explain your second error, but if you take the Point option for the line end you can snap to the end of the arc.

Both examples work correctly in Rhino 7…

Regards
Jeremy