View Full Version : Circular bone? Sphinkters?

05 May 2011, 01:32 AM
Hi all. I've looked all over the web and haven't been able to find much about this subject.

I'm modeling and trying to animate a digestive system, and what happens when food goes through it. I need to be able to change the width of the esophagus as food passes through it so it appears somewhat realistic. I need like a circular bone that will expand a cylinder in equal directions. I've studied of course how you animate a mouth, and it's done with 4 bones, but this seems like it would be a major pain trying to animate every section of the esophagus as the food goes by, and the expansion wouldn't be equal. Is there a better way to do this?

05 May 2011, 04:04 AM
One possibility is binding an FFD-Box spacewarp to the esophagus geometry and animate it with a Path-Constraint (with "follow" on). Hope it help. :)

05 May 2011, 04:06 AM
Hmm. What is ffd spacewarp in? My primary tool is 3dsmax, but also have c4d. You think Maya would be better at this kind of thing or something else?

05 May 2011, 04:10 AM
Oh that is 3dsmax. I haven't used box spacewarps much. I'll give that a try...although I have worries that it would deform it uniformly again.

05 May 2011, 08:08 AM
Or you could animate a gradient ramp along the geometry and use it to drive a 'volume select' modifier with a 'push' modifier on top.

05 May 2011, 04:12 PM
Create a circle spine and have a ring of point helpers attached to the circle with a Path constraint,(offset the helpers using the percentage value) then have stretchy bones between the helpers. You can then increase of decrease the circle radius to open and close.

I wrote a script to create this from scratch once I shall try to dig it out.

05 May 2011, 04:02 AM
Thanks for all the suggestions. I'll definitely give them a try.

05 May 2011, 03:55 AM
I think I might have found a solution to this using bones pro, a plugin. Haven't completed it yet, but it definitely looks good from the examples I've seen. They have an example on youtube that shows exactly what I need with a muscle deformation using an object which is turned into a bone, which then deforms the mesh.

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05 May 2011, 03:55 AM
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