Hello,
I am new to rhino but can`t find an adequat solution to my problem. So I want to move the right point of my curve (which is an circular sector) lower, like its shown in the picture and let the left point of the curve static. But because of the middle point it only moves half of the curve and not the coplete smooth. At the end the curve have the same gemometry (circular sector) in floor plan ?
Thank you 
can you sketch the desired curve ?
you want a helix ? there is a _helix command
what are you after ?
rhino s nurbs representation of arcs will have 2 spans for 90..180 degree.
(and 4 spans for 360 degree). (and are degree 2, rational, - a mathematical perfect arc)
you can draw arcs with “deformable” option to get an non-rational degree 3 approximation
or _rebuild an arc / circle
… both to get more cv-edit capabilities.
