Newbie: Need "grow" a rigged tentacle?
 

I am trying to create an effect in which, over a number of frames, a tentacle grows from a character which is then used as an extra arm (kinda anime-ish).

In an ideal world, I would like to have control over the tentacle's IK handle during growth so that I can whip it around a bit.


(Does this all sound a little too Freudian?)

Might could use blend shapes.

Mike, do you think Lattices might help me here?

sure, that might also work. There are a number of ways.

The main thing you'll need to worry about is making sure the deformation order is correct.

Is this what you're after:

http://www.dannyngan.com/temp/tentacle-playblast.mov

This setup involves using several components:

1) 1 joint hierarchy (orange joints) with a spline IK handle with an auto-created but not simplified curve. This hierarchy, along with the root joint is skinnied to the mesh.

2) [edit] Another joint hierarchy (blue joints) to control the spline IK's curve via a smooth skin.

3) [edit] A multiply/divide utility node to allow the length the spline IK curve to affect the scale of the spline IK joints.

What all this gives me is the ability to scale the tentacle and bend it however I like by transforming the control joints. I didn't add an option to twist the tentacle, but that won't be too difficult.

Danny, that's exactly what I was looking for! I played around with lattices for a couple of hours last night and realised that, to achieve even a mildly interesting result, would require an incredible amount of setting keyframes on lattice points and endless tweaking.

While reading the docs, I discovered the IK Spline Tool and had completed step 1 of your trio. Unfortunately, I was completely stuck on how to grow it... what you propose in steps 2 and 3 is great! I would never have thought of 3.

Many many thanks, I'll be trying that tonight.