Follow path and deform


Just a guick question…
This has been working in 2.49 before as far as I can re-call, but I just wanted to do an experiment if this is achievable.

So what I’ve done so far is created a bezier circle and wanted to make a circle-shape-mesh (actually made of a top cap of a cylinder) to follow it while it deforms.

Also I wanted to lock the circle-shape-mesh to the path.

I have applied the “curve” modifier and the clamp to “constraints” but I don’t understand the logic behind the movement of the circle-shape-mesh.

I am not sure if it is clear, but I have uploaded the blend file to here:

There might be a very simple solution, I just can’t seem to be able to figure it out.
What have I done wrong?

any help is much appreciated…


You should just need to key the location for your mesh circle, as explained in the wiki for the Clamp To Constraint (describes it for 2.49, but looks like it’s pretty much the same for 2.58):

I wasn’t sure if you wanted the bezier circle or mesh circle to deform, but you can use shape keys to achieve this for either (I assumed the mesh):

Thanks Gimble,

Yes, it works fine! Taking down the influence to 0 and translating the origin of the mesh horizontally helps.
I wanted only the mesh circle to deform according to the curvature of the path. It works well now!
I have updated the file for small experiment:

Here I added a cylinder which moves along a bezier curve and deforms.

What makes me confused is that the origin doesn’t stays in the centre of the object.
I was expecting to be able to drag the mesh object freely in perspective view without it (or it’s origin) leaving the curve or path. Basically I thought that clamp to locks the position of both (mesh and origin).

Anyway many thanks again for having a look at my issue…


Ah, ok. I see what you wanted to do.

Actually, you don’t need the ‘Clamp To’ constraint at all. You can just delete it and get the same result with the ‘Curve’ modifier.

Sorry about that, I was a little confused. I haven’t used the ‘Clamp To’ constraint before. It appears that it’s just a quick way to “clamp” an object to a curve when you’re only concerned with animating its position along the curve (as opposed to situations where you also want to have it rotate as it moves along the path), in which case it would be better to use a ‘Follow Path’ constraint.

Here’s a good example of the use for the ‘Clamp To’ constraint (for 2.49):

Yes, you are right. It works without the clamp to constraint either.
Actually for this purpose I could even get away without “follow path” too.

Here is an update with the follow path and the curve modifiers

The reason why I wanted to try “clamp to” to restrict the motion path of the mesh (like on the great example you sent) even if I just click “g” in perspective mode and grab freely, however I also wanted it to change shape according to the path it follows. Now I understand that it is not quite possible.

The solution is to use “curve” modifier and translate the object along one single axle. (if I grab, it will leave the curve or path it should have been clamped to)