Welcome to od|forum

Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customize your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more! This message will be removed once you have signed in.

primzahl

[Beginner] L-System / Branches

Hello,

I'm following the Tutorials from this site and Workshop No.8 is a nice introduction for L-Systems. In exercise No. 3 you should try get the given shape. Well, I think, I set up the rules to get close to the sample, but I couldn't find out one thing. I read the help-files and played around with some variable, but I couldn't find a Solution:

As you can see the branch 'C' scales down and decreases by (in?) generation. But as in the sample, it should only scales down. How can I do that?

primzahl

post-3305-1237200563_thumb.jpg

post-3305-1237200620_thumb.jpg

post-3305-1237200727.jpg

Edited by primzahl

Share this post


Link to post
Share on other sites
As you can see the branch 'C' scales down and decreases by (in?) generation. But as in the sample, it should only scales down. How can I do that?

FWIW, i can't duplicate the original Lsystem either, but I'm no Lsystem pro.

anyway, a few "observations" :

if you zoom in really tightly to the source pix, you will notice that "C" in the source does, in fact, decrease over "time" (generations). it just doesn't decrease as fast as as yours. ;)

i see the "dimensions" of the source shape to be approx 5 grid squares tall and 7 grid squares wide. whereas yours starts off fitting entirely inside one of those squares!! technically 0.25 of one square! this might not apply to any of this, but it might help.

here's a doozy! they never mention that "C" needs to grow over time. in other words, why not create it with a few generations ( pre-grow it ) and then open up the comments and copy the "Lysystem string?" OK OK you can do this rather easily by hand copying and pasting the original rule, but if you want you can also go to a textport and use "opinfo." you can even drag and drop the Lsystem node rather than typing in its path.

my guess is, it is a variant of this. probably a couple repeated "iterations" and then the call back to "C" again.

other than that, you might try emailing the author / instructor.

lastly, please keep posting your results.

good luck. peace & 42

Share this post


Link to post
Share on other sites

Primzahl,

As odforceuser42 said, it is just a matter of size. My "C" also "decrease", not just scaling down. However, I used larger number of generation and smaller "Angle", so it looks like just scaling down.

Attach my file. I also tried your rules (in lsystem5). If you really want "C" to scale down without decrease, may be you can try "nested lsystem"? I tried it in lsystem6 and lsystem7.

Kam

09_ex03.hipnc

Share this post


Link to post
Share on other sites

hallo,

sorry for my late reply, I'm very busy with some papers for the university and so Houdini has to wait ... :(

Thank you for your reply

Share this post


Link to post
Share on other sites

Primzahl,

You are welcome. Thanks for reading my simple pdfs. Please point out any mistake I made in the pdfs if you find...

:)

Kam (icelab)

Share this post


Link to post
Share on other sites
Hello,

I fight myself through to

Edited by sam.h

Share this post


Link to post
Share on other sites

I guess you cannot use X to replace G, as G is a special symbol and it will move forward, but X will not. That's why primzahl's final version lost all the notches. sam.h's method looks closer to the original example.

BTW, the help page of Lsystem SOP mentioned that it supports context-sensitive syntax, but I have never tried:

[left_context<] symbol [>right_context] [:condition]=replacement [:probability]

Share this post


Link to post
Share on other sites

Sorry for my late answer, at the end of June there is always stress at University.

Thank you both for your Inputs and for the file icelab, it help me a lot. and you're right, "G" can't easily replaced, I was in some way aware of it, but I had to much twistSOPs in my brain. :D

I used both ideas to get the shape.

post-3305-1246616814_thumb.jpg

Edited by primzahl

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now