PDA

View Full Version : Cloth Dynamics in LW - Specifically precise control

aswhitehead
04-27-2007, 12:25 PM
This is a cross-post from Spinquad. I know a lot of people are on both but wanted to post it here as well for feedback.

Say I have a long lightweight ribbon that I apply cloth effects to. One end is fixed and using a wind generator, the other end is blowing all around. I know how to set this much up. But I also need to take a "ring" and run it down that ribbon and the ribbon needs to stay inside of the ring wherever the ring may be. The cloth can control the ring or the ring can control the cloth - I just need to be able to have some control over the ring object as far as keeping it in camera and speeding it up/slowing it down.

A couple of ways I have thought might work I have listed here but since I am quite new to Cloth FX I need your input:

1. Make the ring and cloth object on the same layer. Create a morphs with the ring moving from one end to the other. Then attach that model to the 2pt polygon chain.

2. Set the ring as a custom collision object and run it down the cloth during simulation?

3. Somehow use a collision object under "Attract" mode to keep the cloth with the ring. (Not even sure what Attract mode does but thought it sounded like it might work)

4. Somehow use a bone/null combo to make the cloth follow the ring? I know that Howard has done this on the ends of an object (like in his Power Cord sample) but not sure it will work in the middle of the cloth object and move down the object.

Anyway, will any of these work or are they all off base? Does anyone have a better solution?

Thanks,
aswhitehead
aswhitehead
04-29-2007, 02:12 AM
Anybody got any ideas?
Bonzodogboy
04-29-2007, 02:27 AM
One technique that I have found quite effective, is to apply clothfx to both objects.
Set the ring clothfx to fix all, and collision set to all, but leave the original parameters alone.
then set up your cloth object, animate the ring and then calculate the result.
Also be careful with the scale. If it's too small, then the results can be really crappy and jerky.
there is a sample scene around on this forum, by robertoortiz. it isn't exactly the same as what you are doing, but you could get some ideas from there as well.
also it may pay to use several collision nulls to help control "buggy" areas.
aswhitehead
04-29-2007, 02:58 AM
Bonzodogboy - That is a good suggestion. I will try it out.

there is a sample scene around on this forum, by robertoortiz. it isn't exactly the same as what you are doing, but you could get some ideas from there as well.

Can you point me to this? I did a search for his posts and found a flagpole animation. Is that the one you are referring to?

Thanks,
aswhitehead
Bonzodogboy
04-30-2007, 12:05 AM
yeah, that's the one. All the same principles apply.
the flag is basically your ribbon. play around with collision offset on both the ribbon and the ring.
murcielago
04-30-2007, 06:29 AM
Not sure what the difficulty is. Setup the ribbon with bones so you can pose it the way you want it to start (ribbon running thru the ring). Make the ring a collision object. Apply clothfx to the ribbon. Animate the ring and then go back and hit the calculate button. Animate the camera to follow or target the ring.
CGTalk Moderation
04-30-2007, 06:29 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.