# Twist in Grasshopper keeping same object proportions/lengths etc

Hi I am new to this forum so please excuse me if I am using it incorrectly.

I have been wanting to twist curves + objects both 2D + 3D in a way that the lengths I choose stay exactly the same, but their orientation has been rotated. It’s slightly difficult for me to explain what I mean, but for example if you where to hold a bike chain and twist it, the chain is still the same length but it has curved and contracted, if you where to measure it whilst being twisted it would be the same length just its orientation would not be straight/true.

I know this might be a strange idea but for part of the model I wish to create the lengths and divisions need to be accurate to within a 100th of an inch. The reason for the twist/orientation/rotation is to accommodate body ergonomics.

If I haven’t explained well enough then I am happy to explain further and send a few pictures if that would help.

Thanks!

Dusan Harkin

[quote=“EricM, post:1, topic:6572, full:true”]
Is it possible to use the Twist command in Grasshopper? I have two curves and I want to twist them like I would with Rhino.

How are you twisting it?

Here is a link to a related topic on the GH Forums to do with Helix to Line where the length stays the same.

Thanks for the reply! I am starting with straight/true lines/curves (e.g a flat 2d rectangle 30’ x 10’) and wish to rotate it down its longest mirror line (30’) by 15 degrees clockwise keeping the all lengths the same, just the orientation changing by 15 degrees.

The first video in the link uncoils the helix into a straight line, but the geometry of that isn’t quite what I’m looking for as it is based on circles/helix and doesn’t used lines of symmetry. The second video response on that thread shows a scripting method where the parameter/boundary length stays constant but the curve it self doesn’t stay the same length as you can see more length is added to fit its parameter.

I hope my description was clear, if not let me know if I should post diagrams of what I mean.

Cheers!