L-System Helix

[bandini]

Anyone know how to make a helix in L-Systems?

I can make one using some basic rules (below), but it is always off-axis, pointing in a strange direction.

Using:

FA

A-> +/FA

Just looking to make one that goes straight up.

Edited July 18, 2010 by bandini

[Macha]

It's very rough hack, but try this as your premise:

^(135)/(13)FA

Edited July 19, 2010 by Macha

[bandini]

It's very rough hack, but try this as your premise:

^(135)/(13)FA

Thanks, Macha, but changing the angle value will cause problems. I'm looking for a more generic solution where I can continue to play with angle, spacing, growth, etc.

[Macha]

It's trickier than I thought!

It's maybe not what you want but the following expression creates a customizable helix, but the problem is that it's presumably (for your purposes) connected wrongly. You could fix that afterwards though I guess. I'll keep digging and see if I come up with something better. I'm sure I did one of those in the past.

Premise A

A = [&(90)F(2) D]F(0.1)/(410)A

[Macha]

screenshot

[Macha]

Ok, I had a moment to look at it, and this appears to be exact, with the option of tapering as well:

Premise: A(1)

Rule: A(s) = +(58)/(4.2)"(4*s)F(s)A(1*s)

[Macha]

screenshots

[bandini]

Ok, I had a moment to look at it, and this appears to be exact, with the option of tapering as well:

Premise: A(1)

Rule: A(s) = +(58)/(4.2)"(4*s)F(s)A(1*s)

Hey Macha,

Thanks for doing that. I don't think its exactly right, though. Look at it from the top view and play with some parameters. Still get's wonky or goes off axis.

Someone at work showed me a way to get a helix. I think it is still a bit of a hack, but it definitely works. It uses tropisim to get the spiral pointing the right way:

Premise: FA

Rule: A = /+FTA

Set gravity to -50.

I think it still is a bit of a hack though. Would be nice to know what the "correct" way of doing this is.

Edited July 20, 2010 by bandini