Spirals in grasshopper

Replies to This Discussion

Permalink Reply by David Rutten on December 18, 2016 at 4:39pm

The spiral you drew is pretty non-specific. It doesn't seem to obey a straightforward mathematical rule. I attached two different approaches. One which creates a series of shrunk repetitions of the base shape, then connects them all up, the other generates all the points of the spiral first, then scales each point slightly more towards the centre.

Attachments:

• spiral_maybe.gh, 16 KB
• spiral_perhaps.gh, 14 KB

Permalink Reply by David Rutten on December 18, 2016 at 4:42pm

And here's a third approach which moves all points inwards at a constant rate, rather than an exponential one.

Attachments:

• spiral_otherwise.gh, 14 KB

Permalink Reply by Jesus O. Villarreal G. on December 19, 2016 at 5:51am

Hello David!

Thank you for your quick reply! That is exactly what I want to do but it is really nice to know how to generate a spiral from any polygon! thanks for that! Actually, I want to generate and spiral from a complex geometry. The geometry is based on a triangle but the edges are arcs with rounded corners, like the following image.

Is it possible to do that? or it is really complex do?

Permalink Reply by David Rutten on December 19, 2016 at 7:16am

Whether it's hard depends on how you define your arcs. It's pretty trivial to replace all the linear segments of a polyline with arcs that have a consistent deviation from the base line at the centre.

First step is to explode the polyline into individual line segments, then replace each segment with an arc and ultimately join the arcs into a single curve again.

Attachments:

• spiral_arcs.gh, 17 KB

Permalink Reply by Jesus O. Villarreal G. on December 19, 2016 at 10:00am

Hello again David!

Thank you very much for your help! This is exactly what I was trying to do!