What method to get curve tangent from one curve to another?


see attached
I need a sweeping curve leaving A and sweeping into B to finish off the shape.
Its just got to look good.
I use the ‘curve interpolate points’ (my fav curve draw tool) start tangent and click circle somewhere around ‘A’ then see it want to start off exactly at that click, whilst I had hoped for a sliding effect, it choosing best fit when I had clicked somewhere near B.
tangent curve a to b.3dm (27.6 KB)
its not right its asking me to choose the point on the curves where perfect tangent is found as I dont know, we rely on the tool to decide that.



Hi John,
but thats not a sweeping curve as per post…
see image now also in post#1

If you want a circular arc, try the TTR circle and trim away the part you don’t want.

“Sweeping curve doesn’t really mean anything”.
Can you be more specific?

If you want a higher degree curve, maybe try a BlendCrv and pull the defining points around where you want them.

I thought BlendCrv would do it but i get a mess.
what is TTR ?
sweeping curve in my mind means a nice transition as per my image but that has a slight bump, I want it without the bump.
It can go from somewhere nr A to somewhere nr B. Beyond B this matches the shape I am tracing, and the circle at ‘A’ is correct for the end of the item, I just need to get something curvey flowing from A to B leaving A as tangent and feathering into curve at B as tangent.

such that the curve graph shows a nice graph as if it was drawn as an elipse, an elipse on this ends up beyond the object I am tracing.


TTR = Tangent Tangent Radius.
It’s circle option.

I think BlendCrv is your tool. Set to G2 Curvature.
Drag the end points about where you want them, then move the points farthest from the ends to get a smooth transition that is as bulgy (or not) as you want.

Hi John,
I will try BlendCrv again, despite using tangent A and B it was a mess,

TTR did the job with ‘sliding’ start stop points and when I saw the curve I wanted I noted the radius and typed it in then hit enter,
is there a way with TTR of just clicking to end and getting the radius being displayed at that moment, as I always end up with last used setting.
is TTR technically correct for my scenario A to B , both are tangent so I would think so.


Steve -

No, but instead of using the Radius option, you can use the Point option to simply place the third point where you want it.