Arc three points through curves

Hi !

I have been creating two curves and a dividing line through it and would like to
create a three point Arc now. I saw a tutorial video where the guy just drops the line up on the surface
but it’s not possible. I have a german version so I dont know exactly how the word drag is translated ?
And if I type in drag in german and try to drag it it doesnt work.
So he is just dragging the middle line and it becomes a three dimensional object.

I just need a link to a clarifying video that shows how it works.


Hi Laura,

Is this really a Grasshopper question? Drag is probably “Move” in English.
It would help a lot if you could share the video you’re confused by.

It’s video 5 creating biarcs. The very first minute when you drag the line.
I tried it but the line just moves like a curve. Its not becoming a 3D object.
What type of command do I have to use ?

I hold down Ctrl to move objects perpendicular to the CPlane while dragging them. This only works for objects inside the Rhino document, because you cannot select and change Grasshopper geometry using the mouse in the viewports. Since the Rhino curve is referenced by Grasshopper, that drag eventually causes GH to update.

Thanks a lot !