Animating Extruded Base Curve via Armature

First off, when I say extrude, I mean extrude as in “Extrude” parameter in the curves & surfaces panel.

I have a curve that defines the profile of an object that I then extrude in the curves panel. I need to deform this base curve with an armature, hopefully without having to convert the object to a mesh.

I can’t get it to control the curve as the ends of the object are outside of the armature’s envelope. The base curve, is very much inside the envelope when I’m in edit mode of the curve object. I can change the shape of my object with the armature if I set the extrude to zero, but that is of course no help to me.

Since this is a curve object consisting of control points instead of verticies, I can’t control it via a vertex group so that is out.

Since I need the selected control points to rotate, I can’t use a shape key because… well, shape keys don’t rotate control points, they translate them from point a to point b.

I hope I’m explaining this correctly :slight_smile:

I’m not sure what to try next. Any ideas?


You could use hooks (I hope you don’t need to may of them).

Hooks work. Mostly. (Never used hooks before… thanks for the tip BTW).

My empty that controls the hook seems to get placed in an arbitrary location. It’s not placed at the center of the main object, the center or the selected verticies, or the cursor position. It will work like that, but now I need to be able to have a constant pivot point in relation to the main object.

Having the empty placed at my pivot point would make for easy rotation, but I can’t seem to relocate it. Setting the hook center to the cursor located at my pivot point doesn’t work either (with “recenter”).

I’ve had to parent my hook-empty, to another empty at the pivot point. Then I rotate the pivot point to make things happen. Then I’ve parented the resulting pivot empty to my object so it all moves with it.

It will work… it just seems a bit messy. I’d love to entertain more ideas :slight_smile:


BTW: There is some very odd undo behaviour working with this hook that will basically break the position of my base object in relation to the hook. I’d love to try to reproduce and file a bug in the tracker.

You could just use RVK’s on the curve; hit I-Key in Edit mode and at the bottom of the popup you’ll see “Curve”. This allows you to move verts relative to the Object Center using any number of keys (actually I think the limit is 32)

Jean has three tuts on RVK’s here:

and here’s what the old manual says:

Sure, my first attempt was done this way. But these verts need to rotate around a point while animating. With RVK’s they don’t rotate, they move in a straight line. Although the first and last frame show things where they should be, the animation frames in the middle have the model looking quite wonky.