Messed up intestine animation with lattice modifier

Question

I have modelled a digestive system. I have to animate the food movement inside the gastrointestinal tract. I have learned to do it with lattice modifier from another post. I have done it for the food pipe. When I tried to apply same for the intestines the animation is somewhat messed. I created intestine, made a bezier curve in the shape of intestine and created lattice to deform the intestine. When I made the lattice to follow the path of the curve the deformation occurs but the other parts of the intestine are also affected by the lattice which makes the animation so messed up. Please help me get a clear animation of material through the intestine...I have attached a gif of the animation which I got...

Answer 1

When using lattices, it's quite important to keep the outside undeformed where necessary. Ideally two rows of verts, not one. If you don't, the deformation will extend to infinity and beyond.

As you can see, the left lattice still deforms both cylinders.

The selected cylinder is almost but not completely untouched. Two rows are bullet proof though.

Hm, the end of that animation should yield interesting results.

Answer 2

For the animation you're trying to do right now, maybe the Cast modifier would make it easier:

• Create an empty.
• Give your bowel a Cast modifier, with the empty as the Object. Put it above the Subdivision Surface modifier.
• Play with the different factors of the modifier so that it has the shape and influence you want.
• You can even create a second empty with a negative Factor if you want your bowel to contract (it doesn't seem like you need it this time though).
• Move your empty along the bowel (the easiest way is to make it follow a curve).
• If you want your modifier to only affect a part of the mesh, give your mesh a vertex group and choose this group in the modifier.