Elliptic Spiral moving in space - HELP!!!

Hi guys, I've built this spiral manually in Rhino for a project and I was trying to find a way to build it in Grasshopper, so that I can adapt it to different curves and control its shape.
I've found some tutorial about spirals, but I find quite hard to build an elliptical one...

The spiral is obtained by linking ellipses that have all their centers on a curve (red curve). My ellipses base planes were reciprocally parallel and all perpendicular to the (x,y) rhino plane, but I'm not sure if this is essential to obtain the spiral.

I know it's an hard request, but maybe someone of you has an idea about it...all suggestions are well accepted, I'm just a beginner!

Thank you!

Attachments:

spiral.jpg, 352 KB

Replies to This Discussion

Permalink Reply by David Rutten on November 22, 2009 at 12:04pm

Hi Giulio,

spirals can be defined in many ways, do you want equal angles? equal slope?

Once you've defined your ellipses, how do you want to make your spiral? Using Interpolate Curve?

--
David Rutten
david@mcneel.com
Poprad, Slovakia

Permalink Reply by Giulio Tarquini on November 23, 2009 at 4:14pm

Hi David!
I'm trying to evolve a structure that I've applied to the spiral I've drawn.
I join two simplified images of it.
The structure can stand only if the ellipses are all on planes perpedicular to the ground.
I still don't know how to obtain a spiral from the ellipses.
I join a grasshopper image where I've tried to build a spiral from circles, following a tutorial.
The problem in this case is that, using "frames" the plane of the circles are perpendicular to the curve and not to the ground, and then I really don't know how to substitute the circles with the ellipses....cause I've used functions and for the circles its easy ( 2*Pi*x), but for the ellipses I should use integrals and I have no idea how to!

Attachments:

Exploded2.jpg, 145 KB
Assembled2.jpg, 236 KB
spirale.jpg, 254 KB

Permalink Reply by Vicente Soler on November 22, 2009 at 12:07pm

You seem to have like 3 ellipsoid surfaces around your line. I'm not sure what exactly you want to achieve. This, for example, is one way of creating a spiral along a curve that's shaped like a morphed ellipsoid:

Permalink Reply by Giulio Tarquini on November 23, 2009 at 4:20pm

wow! cool...
as I was saying to David I need a spiral with an elliptical shape, but the planes of the spiral ellipses should be all parallel and all perpendicular to the ground.

anyway...your spiral is a big step ahead for me anyway....I'll try to follow all your passages and understand them...as I'm just a beginner! ;)

thanks you so much!

Permalink Reply by Vicente Soler on November 23, 2009 at 4:51pm

Replace the frame from curve component with the XZ or YZ plane component and connect the P output of the curve length component to the origin input of the new plane component.

Permalink Reply by Giulio Tarquini on November 23, 2009 at 5:17pm

Ok...I'll try to....
thank you again! :)

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