Rebel object in a facial animation

Hi ! A long letter for a great problem ! I have re opened a blender project of facial animation, in order to apply what I learned since i did it. It is a not so ugly woman face (with an helmet, because I am not satisfied of her hairs : not smooth static particles that give her a look of hedgehog, but it is an other topic).

Here is the problem : I have made a nice dentition : two dentures, one for the upper jaw (parented to a static (non animated) null bone at the top of the head. This has no problem, because it is static. The second one, for the lower jaw, that doesn’t want to move according to the jaw.

I precise that my woman head is made of one mesh (except for the realistic eyes that can follow an empty by track constraint for animation, with numerous Vertex groups affected by different wheights. The lower jaw, the chin, the cheeks are parts of the mesh, and subdivided in several overlapping Vertex groups parented to the armature. When opening the mouth, the lower Jaw and the chin, wich vertex have a weight
set to one move normally without any nocieable deformation, and the cheeks follow, with a smooth deformation. It is OK.

But According to the differences of weights between the different vertex groups, the bone whitc is use as parent for the jaw, get out of the chin. It could have no consequence, because bones are not rendered, but this means that I can’t use the Jaw bone as parent for the lower dentition !

I tried without result all these experiments :

  • Incorporating the lower dentition by joining its mesh to the main head mesh, and giving its Vertices the same weight the jaw vertex have a the same place (1.000 because the front of the jaw an the chin are not deformed during moving). I Also tried with other Weight, without more result. I Equally joined some vertices by edges to vertices of the main mesh, with the hope they act as anchors… :o)

  • Parenting the lower dentition to :

    1. A vertex of the chin.
    2. A face (4 close vertices) of the chin.
    3. A group of vertex (Not a vertex group!) belonging to the jaw and the chin around the dentition.
    4. An Empty parented to the a Vertex, a face, a group of vertices, a bone.
    5. I used constraint to keep the dentition in the good position and direction (copy rotation, copy location)
    6. I added null bones and use them as parent for a best location of parent origin.
    7. I have checked the Ipo (even if I Knew I didn’t made any Ipo for the dentition, because I formerly had problems with rebel objects, due to forgotten Ipo curves).

All that with no result at all ! Whatever I do, the lower dentition goes down, out of the chin when I move down the jaw bone.

If somebod has an idea, I have my eyes and ears wide opened !

to make it short:

the lower dentition goes beyond the jaw, did i get this right?

what i don’t understand is the parenting problem. if you have the lower dentition as a separate object, you can simply parent that to the bone that moves the jaw. select lower dentition, then select the armature containing the jaw bone, hit CTRL+P, select from the pop-up-menu “Bone” and you’re done. with that rig the jaw bone deforms the jaw part(s) of the mesh and also moves the lower dentition.

however the best idea would be to post your .blend file and let us have a look at it. in most cases this is more efficient then theory and long posts :slight_smile:


Hi ! Parenting the object “Dentition” directly to a bone is the first operation I did, and I didn’t expected the result ! It is certainly because of the differents Weight applied to the numerous vertices, but the jaw dont move close to the bone. The amplitude of the displacement of the jaw/cheeks/chin is less important than the amplitude of the bone displacement. The dentition follows normally the bone, but the jaw is late !

I have lost too much time with this problem, and I thin that using a bone for this topic isn’t a good idea, so I have just solved the problem using
Relative Vertex Key, as I had done for the other parts of the face (eyelashes, lips…) It is harder to prepare, but easier to animate, because it alows all the commands to be in the same IPo window, dedicated to the woman face.

I’m still thinking there is an other solution, but I’ll see later for lack of time :o)

Thanks for ideas !