How to animate (rotate) the "Bevel Object" (>Curve) of a Curve


I wanted to make sth like this:

So i made a curve , which forms a letter and another curve, which is basically a square. Now i took the square as the “bevel object” for the letter, and i had what i wanted ofc. no problem so far.

Now the animation. So when i rotate the squareish-curve in object mode it has no influence on the letter-curve. Only when i rotate the square in edit mode, it gives me exactly what i want, but i cant keyframe it in edit mode.
I tried rigging the square, but animating the armature also doesnt influence the outcome of the letter-curve.
I cant usw shape keys either, they actually do influence the letter-curve, but you cant get a rotation with it.

It seems that i maybe need to animate(rotate) the origin of the square-curve, but how can i do that?
(I couldnt find anything helpful somewhere, its hard to describe in one sentence that makes sense…)

How can i achieve sth like in the .gif?


You can do it like this:

So, you add a bone to an armature for each vertex in the Bezier so that they are in line with the vertex points.

You add a Hook Modifier for each vertex point in the curve and set the Target as the appropriate bone. Do this in Edit Mode and assign the vertex to the bone in the Hook Modifier. This constrains the vertex so it cannot move in any direction or rotate about anything other than the Y Axis of the bone:

The you add the Bevel Object and simply rotate the curve about its primary axis - X in my case.

I have added an Empty to drive the thing, so you don’t have to worry about the Bezier “back-flipping” as you rotate it. (you need to check “Autorun Python Scripts” in User Prefs => File Tab or the driver won’t work).

Herewith the blend file: rotate-bevel.blend (482 KB)

Cheers, Clock. :eyebrowlift:


I forgot, this is your first post - Welcome to BA!


The beauty of this is that you can also move the bones in Pose Mode to reshape the curve…

Another possibility is animating the tilt of the letter curve object, but the problem is that by hand it can be done only for single vertices, not for all at once (Tilt property in edit mode in the N panel of the letter-shaped curve), so you’d need a script if there’s a lot of vertices in the letter (or do it by hand for each single vertex)

Edit: better: Shape key the letter curve, not the square. This is perfect. For the shape key, select all vertices and edit their Mean Tilt value in the N panel. Then simply animate the shape key.

See the file.
First curve is animation of the letter curve vertices (I did it in 3 steps, but it doesn’t make a difference).
The second curve is animated with shape keys (Tilt value changed).

Adding bones for such a simple task seems a bit over the top for me, but it’s a valid method too. However, will also need scripting if there are a lot of vertices.

You can animate curves without hooks and armature, using the animall add on.

Thx so much guys!! im gonna check it out as soon as im back home. I dont really got 100% just from reading, need to try this in blender :slight_smile:

Thanks for that @Photox!

Here the revised version:

So, I activated Animall - then selected all vertices on frame 1 and clicked “Insert”. Then I went to frame 101, tilted all vertices to 720deg in the N menu - then clicked Insert again (on Animall panel). Voila! Thanks for the heads-up :yes:

Here’s the revised blend file: rotate-bevel.blend (482 KB) Just press Play again…

Cheers, Clock.

Thx again, i figured it out. Didnt know about the Tilt function, nice!
Sad that you cant Keyframe all vertices at once…

^^ You can with Animall - just select ALL the vertices, tilt them by keying a value in the Tilt box then click “Insert” button on Animall Menu on the left side - it then adds keyframes for ALL vertices in one go.

Cheers, Clock.