[HOWTO] Give your curves IK

Hey folks, this may have been obvious to some people, but if anyone is interested in knowing how to get your armature IK to have an effect on a curve, I’ve put together a small HOWTO. The gist of the thing entails using Hooks to simulate the functionality of weight painting. Until we can actually get armatures to work on curves and NURBS, this is a pretty decent solution. This way, you can do rigged 2D animations like in Moho… and you can probably even rig a fully NURBS model for IK.

Here’s an OpenGL render of it in action:

Check it out and let me know what you think. Hopefully someone else besides me finds this helpful.

Neat! I used Hooks and ShapeKeys the other day, but an IK is irresistable. So I groked .blend to test it and it made a loud click.


It was a good “click”, I hope. :slight_smile:

Yes yes. this is very usefull. I’m adding this piece to this thread from my mechwarriro project:

-Dynamic pipes are done using path, a bevel curve to create the tube along the path, Hooks that attach evry single control point of the path, a chain of bone that follow the mech’s skeleton (using an ik solver). Then all you need to do is to parent each empty created when doing hooks to every bone of the chain, so one bone for one hooks. Here: some shot of the ones on the legs:
-The chain of bones.
hooks placements

Oh yes! Clicks in Blender are like learning a new riff on the guitar; a whole new jive opens up and plays with you.


Excellent, Gabio! That looks like an extremely intricate rig. Do you have any animation of it in motion? EDIT: I just read through your thread and saw the walkcycle you’d done. Very nicely done!

Fligh %, I understand completely.

By the way, I just did a test, and I’d like to note that this ALSO works with Lattice objects. So now you have the option of controlling a lattice with an armature, too.

Another quick update on this…

You can actually use armatures on curves without this technique in 2.40 using the modifier stack and envelopes. However, responsiveness begins to get a little sluggish when you do it that way. Using Hooks as an intermediary, for some reason, seems to work faster.

Maybe someone more informed can explain why?