Create a curve between two curves


I have two coplanar curves (Red and Purple). Is there a simple way to create a curve halfway between the two curves (as iI have sketched roughly in black)? I’ve tried TweenCurves but that creates bizarreness here,

Problem Bisect.3dm (3.0 MB)


tweenCurves works.
you just have to make the two corresponding end points match up. (this step is a little bit confusing to see during the command since the two curves are touching.

after you select the two curves, put the cursor on the intersection of red&purple then click.

then complete the command.



when _TweenCurves fails you might try making a _Loft surface between the two curves using refit value of eg. 0.00001 feet. Then extract an isocurve using _ExtractIsocurve in the V-Direction and click on your point. The extracted isocurve can be improved by using _FitCrv, eg. with a value of 0.01.

Problem Bisect.3dm (36.7 KB)



You can also do this: Problem Bisect_re.3dm (37.1 KB)


Hi Marcus
If I try to open your file with the latest WIP Rhino, I get the following error message

The file was created with a newer version of Rhinoceros.
This file can not be read by Rhino 5.0
@dan @pascal EDIT: Solved … was a Wip file RH6

(Wim Dekeyser) #6

That’s a RH6 WIP file.
Here it is as a RH5 format…
Problem Bisect_re-RH5.3dm (41.0 KB)


Thank you Wim :relaxed:


Thanks. That worked.