Moho Forum

If you open the Rachel character and select Manipulate Bones, no matter how much you move her head, the torso stays in place. I'm trying to accomplish the same thing. I have a group layer for my head and have linked that group layer to the head bone. The torso is in a lower layer and is linked to the Torso Bone. But when I Manipulate Bones on the head bone, the torso eventually rotates. Why doesn't it stay still?

Thanks.

The Rachel figure uses bone constraints. Match your settings to hers.

Try adding a second child bone (for the leg, hip, or whatever) to the torso bone. This breaks the ik chain so the torso won't rotate.

Turn off the vector [or image, I am not familiar with this character] layer and click on the bone layer. Choose the re-parent tool in the bone list. This will activate the parenting links of all the bones. The arrows point from the child towards their parent. This will give you all the information you need to replicate the rig.

Thanks for all the replies. This is a very helpful group.

It is true that Rachel uses bone constraints, however that does not prevent the issue described. Looking at the bone parenting is also interesting, but I had already done that. What I had not done, is add the rest of my bones. Silly me, I started with the head, and was determined to get that right before proceeding with the rest of the limbs. What I now know is that adding the rest of the limbs provides "stability" to prevent the head from overwhelming the drawing.

To prove this point, you can take Rachel (which is installed into the library with version 7) and delete the bones in her arms and legs. Then move the head around and you get the same problem I experienced. This is nice to know, but a little frustrating to realize that (regardless of region binding) the way to limit bone "strength" is to increase the number of bones. My quantitative side wants to know exactly how many bones are required for exactly how much control. Unfortunately it seems like a trial and error process.

I hope this thread helps others as much as it did me.

It's not quite a trial and error process. Like a 3d app, AS rigging works in a way that the mesh [vector or bitmap] is constrained by the bone hierarchy. So one bone will control the entire mesh if it is alone. If you rig just the head of a full body character, by placing one long bone from the neck downwards will keep the body in check when rotating the head. If there are some points which do not have a bone near them visually, they will be influenced by the nearest bone. Hence the reason that, despite not having any bones located in them, your half finished rig was moving the points in the body also.

Thus you add bones mainly where you want an area to bend. You can also use secondary bones to control the movement of a set of points [or a single point] to maintain volumes better, etc.

What I'm saying is that, once you're used to how it works, it becomes easier to predict where and how many bones you need to place.