curve on revolved surface

Hi,

I am trying to generate a helix-like curve on a revolved surface through a specified set of points. These points are defined by a intersection of the profile curve I used to generate the revSrf and a second curve that is aimed to control the steepness and the dynamic of the helix.
Unfortunately the "curve on srurface" component does not create a curve that will continuously follow the Surface in a circular manner, instead the generated curve remains on one half of the surface, swinging back and forth. I also tried to mirror one half of the surface and to generate (and join) curves in an alternating way from bottom to top of the revolved surface. This worked out somehow, but as the curves are generated only between two points each, I never got smooth and continuous results.
I hope this makes some sense at all.
In case someone has the time and the nerve to have a look at the file and to give me a clue on how to solve this, I'd be very happy!

Robert.

Attachments:

Crv_on_Srf.3dm, 49 KB
Curv_on_SRF01.ghx, 167 KB

Replies to This Discussion

Permalink Reply by taz on April 1, 2010 at 5:21pm

Robert,

I just had a quick look at your file. The reason for your problem is the seam (or edge) of your revolved NURBS surface. The interpolated curve on surface will never interpolate across the seam.

I'll take another look, but your best bet may be to pull a curve to your surface.

Permalink Reply by taz on April 1, 2010 at 5:24pm

This might also be something similar:

http://www.grasshopper3d.com/forum/topics/elliptic-spiral-moving-in

Permalink Reply by taz on April 1, 2010 at 7:54pm

There might be a more spiffy mathematical way to do this, but here I'm interpolating between points extracted from intersection curves (circles in this case) between your fixed intervals.

This gives you a single interpolated curve that may not be exactly on the surface but it hits all your points.

Attachments: