View Full Version : Circular bone? Sphinkters?

05-02-2011, 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?

05-05-2011, 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. :)

05-05-2011, 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?

05-05-2011, 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.

05-05-2011, 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.

05-05-2011, 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.

05-14-2011, 04:02 AM
Thanks for all the suggestions. I'll definitely give them a try.

05-22-2011, 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.

CGTalk Moderation
05-22-2011, 03:55 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.