Curve Deform and Shape Keys

Blender 2.55

I have a serpent monster curve deformed. Works perfect until I add shape keys to the curve. Then it starts twisting up the mesh.

(Used a subdivided box as a substitute example)

I found this post;

I tried clearing Tilt, nothing. I don’t want to change Tilt, it’s set right.

The strange thing is that in Edit mode the mesh is properly deformed, and even deforms in real time when moving the handles around. Really cool, till I go back out to Object Mode.

It’s like Blenders mocking me :smiley:

Help? Thanks.

Perhaps you should post your example blend file. It seems to work OK for me.

This is for work so I can’t post the original .blend, but the problem repeatedly occurs.

So here’s a .blend that should demonstrate the issue.

Thanks for your help!

Looks like it might be a bug. You could try using a path instead of a bezier curve; I did a quick test with a shape similar to yours and it looked OK. I don’t know if it will work in your case. Hope it helps.

You’re right the deformed mesh with a path is responding as expected with shape keys.

I’d prefer to use the Bezier Curve, those handles allow me to really control the poses of my sea monster.

Were you able to recreate the “bug”? Should I report this?

Setting the mesh to wireframe display allows you to clearly see the curve isn’t tilting or twisting like the mesh is. I can’t explain it. I was just trying to use a bezier curve for the same reason as you shibazz, because of the handles. I was using hook modifiers to animate the curve for a spline IK chain, and for me the curve flips tilts or twists around as well and I can’t explain it. My problem was posted here. Although slightly different, I’ll be watching this to see if I can gain any insights…

Just in case this might be your problem
When I used shape keys…
I think of them as various poses that can be combined
there is a basis shape key and other shape keys in the set of shape keys
any shape key can be used … or ignored … or combined on any frame
determined by weights
In the simple case
For every important frame … I must set the
weight to 1 for the non-basis shape key I desire at that frame
weight to 0 for all over non-basis shape key for the curves I do not desire at that frame
other wise you will get blending … which may not suit your needs
editing will allow you to edit any shape key on a >>frame time independent basis<<
so one can edit and edit and see no animation time change … because the weights may need to be set to some nonzero value
so the shape resulting from a set of shape keys does not have to be identical to the any particular individual shape key
weights are the blender of shape keys
the curves represent the weights in the graph editor
weights determine frame time animation time behavior with the shape keys
you may change the weights to suit your needs

Yeah I see what you mean.

If you add a new bezier curve, duplicate it… apply a bevel object to both . I used a square. Then add a shape key or two (just adding the key does it doesn’t need a new shape) to one of the curves and whallah… it has twisted. It gives an interesting candy cane look if you give them red/white colour.

Surely this is a bug in the shapekey interpolation routine for beziers. It looks ok in edit mode because that is using the original shape curves.

I suppose you may be stuck doing it backwards shibazz if you want to stick with beziers. Duplicate a number of curves twiddle them to shapes and then apply them as shapekeys on your dragon.

I’ve been pushing forward with the path, but I just tested the workflow for applying the bezier deform as shape. Thats a good one too.

I’m having trouble wrapping my head around the “weights” approach, but hopefully one day I’ll have the mindset of a bezier slinger as well. :slight_smile:

Thanks ya’ll. Great work arounds and information.

I think you should report the problem as a bug if you haven’t already.

Just submitted to the tracker: