Problem- Drawing a tangent to two curves

[accellodyne]

Tangents to two arcs are no problem for me. However, I cannot figure out how to draw a tangent to a circle and to a spline or a tangent to two ellipses, etc. Any one have a tip for drawing a tangent to two curves that are not arcs? I have looked thru all the X3 help files and can't find anything but the elementary answers about tangents to two arcs.

[mastercamguru]

Use create-> curve-> create curve on one edge to give mastercam an arc(from the spline) to draw tangent to. You can only select control points on a spline as far as I know.

[accellodyne]

OK, this getting too complicated. How does one draw a straight line tangent to two ellipses in the same way that one can draw a straight line tangent to two circles?

[cadcam]

accellodyne or Skyking01x as you are finding there is no option to create a line tangent to a Spline. there are no true curves to to be tangent to as a spline is built from a set of nod points to create the curve. Some of the people are trying to show work a rounds. there is no magic button that make it easy. Sorry about that.

[cadcam]

Use create-> curve-> create curve on one edge

This can only be done on a surface or Solid.

[mastercamguru]

My bad.

[cadcam]

No Bad for trying to help. that is alwas a thumbs up from ME.

[mastercamguru]

I used create line tangent through point. Here's my mcx. (x2mr2sp1).

[mastercamguru]

Like Jay said, there is no "real tangent point" to an irregular spline. Although this may work in this case, if I rotate each ellipse 10 deg away from each other. It will not work. A control point just happens to be at a tangent, because of its orientation, and because the curve is constant.

[accellodyne]

There is a tangent line to every point on any curve. This is a basic calculus principle.

skyking01x

[mastercamguru]

Yes, but it is not a Mastercam function.
I was only referring to the tangent function in Mastercam.
This is possible to do,but I don't know of a c-hook or net-hook to perform this function.

[mastercamguru]

You can aproximate it using create-> spline-> create blended spline, but it is no more accurate than sketching a line by eye.