Chain

# 1 19-04-2005 , 08:32 PM

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Is there any way to create a realistic chain effect or any type of string like object. Basically i need a chain to be lifted in the air, it is made up of bunch of NURBS Torus. I want the Torus to colide with each other so when i lift it up, the first link is lifted, which pulls the second, which pulls the third etc. Is there anyway to accomplish this type of animation on a cord or string like object?
Thanks

David

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# 2 19-04-2005 , 08:39 PM

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do you want it atached at both ends to something or is it just going to dangle there from one end ?

short anser is you can use a splineIK set up. parinting each link to a joint on the spline. you then add dynamic's to each of the cv's of your splineIK. You do that buy like makeing ridged body cubes at each of the cv places. Put gravity and colistions on them. With springs between them.

Let me know if you want to know more.

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# 3 20-04-2005 , 08:12 AM

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https://www.learning-maya.com./t_rope.php

Although the way you described will also work. What you can do is create each one of you torus' so that they intersect correctly. Then parent a nurbs circle to the middle of each one. Then loft a nurbs surface along the circles thus creating a rope. Make the torus' active rigid bodies, apart from the one you want to move around and affect the others (probably one of the end ones). make that one a passive rigid body. Now key the passive rigid body and your chain should work and if you hide the torus's you will only render the rope.... see it's easy user added image

Alan

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# 4 20-04-2005 , 12:33 PM

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Hey thanks for both of your guys' help. I have a question though about both of those techiniques. First, to Pony, how do you make a CV dynamic, I thought you could only do that to an object.
And secondly, to Pure_Morning, i am a little confused about making each torus intersect correctly, do you mean I should attach them to each other?

My main problem is animating the chain or rope. Because even if i move the top torus, it won't collide with the others, unless i am using something like gravity and playback the animation. Say I move the topmost ring. Even if it is passive, and the others are active, it will still not affect the others.
If you guys have any further suggestions or clarifications i would appreciate it. Thanks a lot though its a great start

David

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# 5 20-04-2005 , 01:17 PM

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intersect them like a chain:

https://www.brumbywatchaustralia.com/chain.jpg

that way when you make them rigid bodies they will collide with each other and not pass through.

user added image

Alan

Technical Director - Framestore

Currently working on: Your Highness

IMDB

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# 6 20-04-2005 , 01:41 PM

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Is there a tool i do to intersect them, or do i just manually set each one next to each other like the picture? And will this allow me to manuall move them, so they collide, or will they still pass through each other when i keyframe?

thanks

David

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# 7 20-04-2005 , 01:55 PM

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use the duplicate tool and set a translation offset and a rotation offset of 90. That will cause them to twist and move into place. You can then set the number of duplications to do. Thus you will have a chain.

user added image

Alan

Technical Director - Framestore

Currently working on: Your Highness

IMDB

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# 8 20-04-2005 , 02:24 PM

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Ok thanks, i think i've got what you have told me so far, i included a screen of my chain, using the circles and parenting them, plus a view of my hypergraph, so you can see if i parented them correcly.
I hope i've don't it right so far.

I also set up the lofted surface and made the riged bodys, but i don't see why I applied the riged bodies to the toruses. Any reason?

thanks again you've been a huge help

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Last edited by Noradul; 20-04-2005 at 02:27 PM.

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# 9 20-04-2005 , 02:51 PM

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ok don't intersect the geometery, link them like a chain. Then apply a gravity field (remove the rigid bodies you've done already and just select the torus' and apply a gravity field that will automatically make them rigid bodies.)

Try that

Alan

Technical Director - Framestore

Currently working on: Your Highness

IMDB

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# 10 20-04-2005 , 03:05 PM

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Hey thanks! That worked great. I really appreciate it!!
I'm getting some weird deformations on the rope, like it is cutting into itself, but i'll figure something out
Thanks again!
David

Last edited by Noradul; 20-04-2005 at 03:07 PM.

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