Drawing a tube (with self collisions)?

[aceOfbaseTen]

Hi.

 

I'm trying to draw out tubular shapes (that will be constrained on a hilly terrain) but also has a self colliding feature. Like a snake going over itself within a given stroke of the pen/mouse.

 

Something like this in modo:

 

http://www.youtube.com/watch?v=GafkLTtOKlA

 

http://www.youtube.com/watch?v=HFJWSuG6Ysc

 

http://www.youtube.com/watch?v=c38tGwuszkg

 

Was thinking I needed to start with a paint geometry sop, then adding a self collision somehow (creep?? maybe?).

 

Also, if just straight modeling can't be achieved, maybe it can be done via dynamics or particles like here:

 

http://www.creativecrash.com/maya/script/particle-strings-smoke-line

 

Thoughts?

 

Thanks..

Edited January 27, 2014 by aceOfbaseTen

[whythisname]

I'm not familiar with Modo so don't know for sure, but the first 2 videos look similar to a curve+sweep (or curve+copy+skin) in Houdini. I don't see any evidence that there is any self collision detection in any of those videos, at least they aren't drawing any geometry that clearly demonstrates self intersection detection/prevention imho. Also if I look at this video (that seems similar to the other ones you posted) it's clear that the geometry self intersects and that the user has to fix that manually: http://www.youtube.com/watch?v=L_oQ0RSu7BY

 

That said, I think you can do self intersections by cutting your curves or geometry in separate parts and detecting collision between them using curvesect (or something similar, the key is that you cut the curve into parts so it becomes as easy as detecting collision between separate pieces). Alternatively Houdini has built in ways to simulate wires and ropes (http://www.sidefx.com/docs/houdini13.0/dyno/wire) or perhaps you can even get away with a spring sop (http://www.sidefx.com/docs/houdini13.0/nodes/sop/spring). Personally I'm not a huge fan of simulations because they cost a lot of time and don't scale very well, but if they solve your problem then they are an option of course. You can forget any real time usage if you go for simulations though which might mean you might as well want the user to solve it.

 

I hope that helps you a bit, but it's not that easy to solve this in a fast and reliable way. Or at least I don't know of any clean way to solve tube/rope collisions.

Edited January 28, 2014 by whythisname