View Full Version : Help Needed - Tubes and Bowels

04-28-2011, 11:24 AM
Hey Folks,

I'm hitting some walls on a project and need some help from the community. Essentially, I have to show a tube/scope snaking its way through a colon. Not only does it need to snake, but it needs to be able to start/stop, flex, and curl up. Additionally, I need to attach a camera and light to the end for POV shots. Fun.

I've pulled from my grab bag of tricks but none, so far, are a complete solution. My latest is to use FI's Bezier Bend combined with a bone/ik tip for flexing but that solution does not allow me to parent a camera to the tip and I don't know of any way to export the motion of the tube in order to then add that to the camera separately.

Other methods I've attempted:

Shift Spline Transform
Bone/Morph Technique

I'd really appreciate the help. I can attempt to manually animate the camera but I'd like to leave that as a last resort, esp. since one task is to cause the colon and tube/scope to loop upon themselves.


04-28-2011, 12:10 PM
Have you tried trailer from Dstorm? I don't know if it's a complete solution but it might be worth a look. It will follow a null so you can parent your light and camera to the that.

04-28-2011, 12:42 PM
I just gave Trailer a shot and though it does a great job of path deformation, it doesn't give me the capability to both flex the tip and also have the cam attached to that tip that bends off the path. The cam remains located on the path/null. Morphs seem to work for flexing the tip, btw, as do bones as long as you set up proper weight maps.

An easier description of what I'm trying to achieve might be the movement of a snake that's looking left and right while he's also moving along the winding path. His body moves forward while he's also able to move his head (the tip) from side-to-side and up-and-down independent of the main motion.

I guess that my main issue at this point is really just getting the camera somehow locked to the tip of the tube as it flexes off the main path.

04-28-2011, 01:55 PM
1) for this kind of thing, I'd expect the bone/morph technique to work the best.

2) for the looking R/L, I'd use morphs.

3) For the camera, I'd search for something that allowed me to track a SPECIFIC point in WORLD space. I've seen such features now and again, but they're pretty esoteric.

4) sometimes, you just have to hand animate things-- not everything is riggable.

04-28-2011, 03:27 PM
Hey Devin, I haven't used LW in a while but...
What if you parent the camera to a null and parent the null to the tube.
or parent the camera and the tube to a null, animate the null for the basic movement of the tube... use bones for secondary movements.
Use morph targets for the "head" motion.

Man, I can't remember, can you animate an "extrude along a path"?

04-28-2011, 03:40 PM
Eric - 1-3 sounds like a good plan contingent upon me being able to find such a point tracking plug-in.

John - The way that LW works, the tube is deformed/displaced from it's original position so that the null doesn't really track the new position when it's placed onto the path. It remains at the original location. Here's where I miss modeler/layout integration.

It'd take some set up but the bone chain may work though it may be just as easy to manually animate the camera.

There are several methods for extruding along a path including the list of plugs that I first noted but it all boils down to the ability to lock the camera to a point on the tip.

Can you parent a camera, null, etc. to a point or cluster in Maya? Just curious.

All - Thanks for the ideas, help, and support. Much appreciated. I'll keep at it!


04-28-2011, 03:47 PM
I wonder if the trailer morph movement could be "baked" in cloth dynamics then grab the desired point's motion with make path in editFX tab and use that motion to drive your camera path?

04-28-2011, 03:57 PM
Thinking out loud....
1) What is it, FX_LINKER? -- you'd do the bone-morph thing to a polychain. Arrange it right and the pivot point is what's moving. Apply the motion to your endoscope via FX_LINKER. (you'd want to do this for speed of animation anyway)

2) Do the displacement, use SCAN in ClothFX to record the deformation (this needs more publicity-- AFAICT ClothFX can record point deformations from ANYTHING) and then use that command that saves out nulls by indexes. It saves a null that follows a motion path, that is. Parent your camera to that null. (Prolly won't do rotations, so you'll still have to POINT your camera.)

--crap, Hunter beat me to it! >;^)

04-28-2011, 06:59 PM
I posted a method to do something like this in this thread: http://www.newtek.com/forums/showthread.php?t=113606


04-28-2011, 07:20 PM
I used the morph along a bone chain method to do this coronary artery stent deployment. Also used morphs to inflate and deflate the stent, balloon and artery...


You basically make a morph map that pushes the mesh along the Z axis. Then curve the object in Layout using a bone chain and use the morph mixer to apply the Z morph to push it along the bone chain. Then use other morphs in morph mixer to make it do other things.

04-28-2011, 09:20 PM
I asked around, and here was what RebelHill said about how to track any given point on an object's mesh:

"DP node item motion on the null, with the vertex in question feeding into it from spot info."

RebelHill is The Man. :thumbsup:

I'm not quite sure how you'd determine which particular point in a mesh is the one in question: you could determine it empirically, by setting up an envelope that would step thru them all.

OR it's possible that one of the Dynamics tools that label points/nodes would display them for you.

If you link thru a polychain, then it's either going to be ZERO or the pointcount of the chain.--- edit: scratch that: you're morphing the tip.

04-29-2011, 08:22 AM
Wow. Thanks for all the responses. It looks like I have a bit of exploring to do today.

04-29-2011, 02:29 PM
Almost... there...

I've managed to get a null parented to a point that lies at the tip of the tube being displaced. Actually, I used the bone/morph method to displace the tube and simply created a point that has the same morph applied and duplicated the bone/morph set up. Using DP's tools, I now have a null that chases the point. It's, for some reason, slightly off but it's close enough.

Now I'm curious if it's possible to use MD Baker or Cloth/SoftFX to bake out the keys of a displaced object so that I can export a proper path. So far, it doesn't appear so. Am I missing something? I've been searching the forums but nothing yet.

I can, of course, manually animate the rotation of the cam that I'll be attaching to the null but now it's the challenge of finding a solution that's pushing me forward.