L-system Question

[cherm]

hi there,

I have a question about L-system. The thing is that I am doing my master project, and in this project, I intend to form a tree trunk with wires. I am thinking about using the L-system to animate wires in order to form the shape of the trunk. From a little knowledge I have, I am thinking about modeling the trunk and having the wires to creep along the geometry. So what I would like to know is that....Is there any way to have the wires to creep along the geometry by implementing the L-system? If not, is there any other alternatives to do so? One thing to note is that I don't want the inside of the trunk to be hollow either; in other words, the inside of the trunk will be full of wires creeping as well. It would very kind of you if any of you can help me out. Thank you in advance.

The below is the really rough photoshop image I created. The wired tree trunk is still not the correct shape that I am aiming yet, but it would give you guys a clearer picture of what I am doing.

cherm

[michael]

have a look at the creep SOP...you can do some very cool stuff with it

[grasshopper]

I take it you've seen (and possibly been inspired by) the wire face that greets you in the Maya 7 splash screen?

The artist is Meats Meier and you could get some ideas by looking at his methods. From what I remember

he paints a lot of the wire look from solid geometry by painting out the 'holes' between the wires. Here's a

link I found from a quick search but you can dig around more to learn how it works.

Meats Meier

This article mentions a Gnomon Z-brush tutorial which might be helpful (I haven't seen it) and I seem

to remember he did an old 3D World tutorial.

Anyway, although this technique doesn't animate too well you could imagine using it for the inner layers

of your wire-tree at least. If you onion skin several layers of your tree inwards you could apply various

versions of this sort of wire texture to each layer and animate the texture (or geometry). I think it would be

a quick way to give the illusion of wires climbing over each other.

Finally, to really sell the shot you could use an outer layer of wires that really do climb over each other.

Two threads on here that might help you with this are these:

Rope

Look for Sum][one's model of a rope which will could help you design your wires.

42 Nodes Competition

This was a contest run a few years back that I went in for. Dig through to the end where

you can download my centipedes hip file. In there you will find a method to allow the centipedes

to climb over each other to fix interpenetration problems (it uses two functions that you can

find defined in the "Aliases and Variables" window under the "Expressions" tab). I imagine it

would translate to your wires very well.

By the way, the centipedes travel along a path that is simply a curve. In my example the curves are

random but for what you want to do you could creep a set of curves along a tree-trunk template

and the wires will then follow the curves.

If you try to run the centipede hip and find it too slow simply turn down the number of centipedes

or even body segments until it speeds up enough.

Hope that helps

John

[cherm]

have a look at the creep SOP...you can do some very cool stuff with it

Thank you so much. I will take a look.

[cherm]

I take it you've seen (and possibly been inspired by) the wire face that greets you in the Maya 7 splash screen?

The artist is Meats Meier and you could get some ideas by looking at his methods. From what I remember

he paints a lot of the wire look from solid geometry by painting out the 'holes' between the wires. Here's a

link I found from a quick search but you can dig around more to learn how it works.

Meats Meier

This article mentions a Gnomon Z-brush tutorial which might be helpful (I haven't seen it) and I seem

to remember he did an old 3D World tutorial.

Anyway, although this technique doesn't animate too well you could imagine using it for the inner layers

of your wire-tree at least. If you onion skin several layers of your tree inwards you could apply various

versions of this sort of wire texture to each layer and animate the texture (or geometry). I think it would be

a quick way to give the illusion of wires climbing over each other.

Finally, to really sell the shot you could use an outer layer of wires that really do climb over each other.

Two threads on here that might help you with this are these:

Rope

Look for Sum][one's model of a rope which will could help you design your wires.

42 Nodes Competition

This was a contest run a few years back that I went in for. Dig through to the end where

you can download my centipedes hip file. In there you will find a method to allow the centipedes

to climb over each other to fix interpenetration problems (it uses two functions that you can

find defined in the "Aliases and Variables" window under the "Expressions" tab). I imagine it

would translate to your wires very well.

By the way, the centipedes travel along a path that is simply a curve. In my example the curves are

random but for what you want to do you could creep a set of curves along a tree-trunk template

and the wires will then follow the curves.

If you try to run the centipede hip and find it too slow simply turn down the number of centipedes

or even body segments until it speeds up enough.

Hope that helps

John

Thank you so much. I will take a look at your hip file.

[cherm]

hi Grasshopper,

for some reasons, I just couldn't unzip your centipede file. I will try to unzip again with the computer in Uni.

[grasshopper]

hi Grasshopper,

for some reasons, I just couldn't unzip your centipede file. I will try to unzip again with the computer in Uni.

Strange. Post back here if you can't get it to work. I'll either re-post the hip or just list the functions for you and tell you how to use them. It's fairly straightforward if you can check out the hip though.

john

[cherm]

Strange. Post back here if you can't get it to work. I'll either re-post the hip or just list the functions for you and tell you how to use them. It's fairly straightforward if you can check out the hip though.

john

hi John,

I finally got the hip file to work, but I don't quite clearly get what you did in there. Can you please explain?

cherm

[grasshopper]

hi John,

I finally got the hip file to work, but I don't quite clearly get what you did in there. Can you please explain?

cherm

All of the nodes have comments on them so make sure you middle mouse button

on each of them to see what they are doing and the custom functions I mentioned

also have comments in them.

The gist of the idea is that the centipedes travel along curves. In my case the

curves are just random paths over a terrain but you could just as easily wrap the

curves around an object and the centipedes (or wires) would follow the curves.

The interesting part is the way that intersections are managed. Proximity POPs

and the custom functions are used to work out when two paths would intersect.

When this is detected the curves are moved so that one arches over the other.

In fact, multiple curves can be made to arch over each other if several intersect.

Each curve is given a 'stacking' priority so that the intersecting curves will stack

up in an order and you are guaranteed to get no intersections. If you can still access

the movie file that was posted in the 42 nodes competition you should notice that

there are times when several centipedes appear to climb over one other.

There's a bit more information in this thread:

Swarm thread

If you get stuck on a particular part ask away but try to be a bit more specific ....

john.

[cherm]

hi Grasshopper,

TestIntersecting.hip

so, you're the NCCA former eh. I am doing my MA digital effect here as well. It's my honour to get helps from you

The thing is that I am not good at scripting and expression thingy at all, so please bear with me patiently. From the attached hip file (the first test), I created two lines to creep along the tube, and I tried to follow what you did. To get the wires to creep along the object was not a problem at all, but however, the problem came when I wanted to have the two lines to arch over each other; they are still intersecting with each other. I think I obviously did something wrong. I just didn't understand about the custom functions (getOrder and getHeight); I didn't know how to get them to work properly. How did you create those custom functions? One more thing is....should I append the polywire sop before POPs or at the very end (after POPs)? Gosh!!! this is so hard man!

One thing I noticed is that the whole POPs thing is so heavy, and my best guess is that with a whole bunch of wires that I will end up with, I might have a big problem.

Here is another hip file that I only tested my creeping wires (still intersecting with each other though).

PoF01.hip

cheers

cherm

[cherm]

I think I'm gonna take a break from the intersecting wires part first. Now I am testing on a wire creeping on a tube which eventually will be modified into a weird shape of a huge tree trunk, and it comes out very well, but the problem is that I just know how to manually create one by one, not procedurally. Is there any way to do that procedurally? I tried to append the copy sop after the creep sop, but it didn't work. Also, is there any procedural method to animate the wires? Please see the attached file

PoF02_creepTest.hip

Please help and please bear with me patiently I will probably be posting lots of questions here until my master project is finished, which will be in September. I really appreciate all the helps so far...esp. from Grasshopper and Arctor. Well, it's only two of you have helped me so far

cherm

[grasshopper]

Hi Cherm,

I haven't had a chance to check your hips yet. Bare with me for a day or two

as we are having a push on shots on the show I'm working on so I don't have

too much free time right now. I'll try to take a peek in the next few days.

You may be right about this approach being too heavy for lots of wires. My

solution was specifically designed to do a lot with as few nodes as possible

which is what the competition was all about. It is very memory intensive!

Saying that, there are usually ways to optimize things and having more than

42 nodes to play might open up a world of opportunities.

john

[cherm]

Hi Cherm,

I haven't had a chance to check your hips yet. Bare with me for a day or two

as we are having a push on shots on the show I'm working on so I don't have

too much free time right now. I'll try to take a peek in the next few days.

You may be right about this approach being too heavy for lots of wires. My

solution was specifically designed to do a lot with as few nodes as possible

which is what the competition was all about. It is very memory intensive!

Saying that, there are usually ways to optimize things and having more than

42 nodes to play might open up a world of opportunities.

john

no problem. I have my test by using the Creep sop.

http://www.divshare.com/download/1299693-805