Modeling a chain

# 1 09-01-2011 , 01:51 AM

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Im in the process of modeling a skater kid. He has a wallet and I want to have a chain from the wallet in his back pocket to his front belt loop. What would be he easy way to make a chain on a loop? I tried using the cv curve tool and create a nurbs torus duplicate it around 50 times and do the snap align objects function- position along curve. When I do this none of the torus intersect with each other like a chain would. I was thinking about trying to use a joint in the middle of each torus and parent each torus to the joint like rigging a snake and doing it like that but that would take a lot of time as well.

Is there another way to make this without having to manually place each torus on the curve?

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# 2 09-01-2011 , 03:02 AM

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For a non-dynamic solution you can use animate>motion path>attach to motion path in conjunction with animate>create animation snapshot

1. make a torus and shape it like a link
2. make a curve as the path of the chain
3. attach the link to the curve (attach to motion path) and play with the number of frames to create the correct number of links for the length of the curve (this is a trial and error process).
4. you want the link to rotate 90 deg for each frame so key the first frame and use the twist property of the motion path and set it to the number of frames * 90 and key it for the last frame
5. create a animation snapshot

There is also a dynamics solution for this but it is more complex. So for a static shot duplication along a motion path is the better approach.

Here is a quick image of the setup and the result of the animation snapshot. You can see I generated 60 key frames for the attach to motion path creating 60 links for the animation snapshot.

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"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675

Last edited by ctbram; 09-01-2011 at 06:32 PM.

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# 3 09-01-2011 , 03:23 AM

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In addition to what ctbram has said, make sure your animation tangents are linear, so that you have equal spacing of links.

-stwert

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# 4 09-01-2011 , 11:07 AM

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Just to add if you are going to do any animation delete the motion path history............dave

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# 5 09-01-2011 , 11:40 AM

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couldnt you also duplicate as many times as needed in polys then combine and add a bend deformer to it...or several?? or will this affect the geo in the link?

bullet1968

"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes

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# 6 10-01-2011 , 03:04 AM

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Hey CTbram, thanks I got it to kind of work. I still cant figure out how exactly you did the 90 degree rotate 90 deg for each keyframe. I cant seem to get them to rotate each frame. Ive never used this animation preset before. How do I use the twist property? Do I adjust it in the channel box?

Thanks for the help.

For a non-dynamic solution you can use animate>motion path>attach to motion path in conjunction with animate>create animation snapshot

1. make a torus and shape it like a link
2. make a curve as the path of the chain
3. attach the link to the curve (attach to motion path) and play with the number of frames to create the correct number of links for the length of the curve (this is a trial and error process).
4. you want the link to rotate 90 deg for each frame so key the first frame and use the twist property of the motion path and set it to the number of frames * 90 and key it for the last frame
5. create a animation snapshot

There is also a dynamics solution for this but it is more complex. So for a static shot duplication along a motion path is the better approach.

Here is a quick image of the setup and the result of the animation snapshot. You can see I generated 60 key frames for the attach to motion path creating 60 links for the animation snapshot.

Originally Posted by ctbram

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# 7 10-01-2011 , 03:19 AM

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joe,

After you perform the attach to motion path you will have a creation node containing the twist property. With the timeline at frame one, right click on the twist property in the channel box and select "key selected". Then move the time slider to the last frame, and set the value in the twist property to (90 x <the number of frames>) and then right click and select "key selected". Now the link should rotate 90 deg at each frame of the motion path.

"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675

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# 8 10-01-2011 , 03:41 AM

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Hey Ctbram, after I attach to motion path I go over to my channel box I have to things listed under INPUT: motionPath1 and makeNurbTorus1. The motionPath1 gives me a U Value, Front Twist, Up Twist, and side Twist. Are one of those part of the twist property?

Thanks

Last edited by joemilkweed; 10-01-2011 at 03:54 AM.

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# 9 10-01-2011 , 05:40 AM

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Front Twist. When in doubt select a property and scrub it to see what it does.

"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675

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# 10 10-01-2011 , 05:01 PM

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Join Date: Jun 2009

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Hey ctbram, I finally got it to work! I wasnt putting in 9000 for the key selected but just 90. These animation presets are really going to help me speed up my modeling time. Thanks to everyone for all the help on this.

Last edited by joemilkweed; 10-01-2011 at 05:11 PM. Reason: Got it working.

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Modeling a chain

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