Rigging Problem Parts Drifting

I couldn’t find an answer for the problem I am having and was hoping it was something simple and stupid. I have a character mesh I am rigging (first real model though version 50 and first time rigging) and for some reason I am having problems with the head bone and parts of the mesh.The nose is essentially just a sphere intersecting the main sphere of the head, the vertices of the nose are not attached to any other vertices of the head. When I tilt the head too far forward or two far back the nose drifts off of the face. I had a similar problem with the eyes but I believe weight painting cleared that up. The character is all one object. I have clears and set any rotation and location of the object as well as the armature. Can anyone think of why the nose would drift off the face? I can’t see that any other bones in the rig have any weight on those vertices so I don’t know why it looks “offset” from the head bone. Any help appreciated, hopefully it is something simple. I am terrible at modeling.

Perhaps also worth mentioning: when I parent the armature to the mesh and choose boneheat weight the parts that are drifting have no weight assigned to them, solid blue. So I have been painting the weight on manually.

Alright, I’ll do it myself. :wink: So after waiting and hoping someone would read this thread and playing around with suggestions from just barely related thread on this and other forums I managed to figure out a solution, I just wish I knew what the problem was. In any case: This is a very simple rig from a video tut. There is a neck bone and then from it, a Head bone.The head bone goes from about the base of the skull to the top of the head at a very slight angle, not straight up and down. I tried to get it to work in 2.5 beta, 2.48b (which is what I am currently working in), I tried moving the object center, putting holes in my mesh, moving the armature and model to the center of world coordinates, clearing rotation on the head bone, nothing changed anything. On a lark, I moved the tail (or the tip as I would call it) of the head bone to the back of the head and then extruded a bone from that pointing right at the front of the face. When I parented the armature with that bone the nose had some weight associated with it. Painting all the head vertex weights to 100% and the nose stayed put except at extreme angles. I reloaded the earlier version of my model/armature I had been using and just moved the tail (tip) of the headbone closer to the face and reparented with heat bone weight and it worked. It was jsut the angle of the head bone. What a PITA!!! Anyway, glad I got it figured out. If anyone here has any thoughts as to why this happened so I can avoid it in the future I am all ears. Otherwise I wanted to at least leave this in case anyone has the same problem.

Sounds like a bone heat problem. Generally, when you parent an armature to a mesh, you also need to create an armature modifier, and then you need to select EITHER, vertex or bone heat, as the method. If you want to weight paint, you need to convert the bone heat to vertex groups, and then turn bone heat off. Otherwise you are applying the same movement twice, and it will mess with the weight painting. Effects like those you are getting, where parts of the mesh move around or fall off, are typical of this problem.

HTH.

Matt

I barely follow that but thanks Matt. When I parented the armature to the mesh I chose bone heat and it created a bunch of vertex groups. I was able to use those groups and weight painting to smooth things out. I guess I don’t understand how the movement is applied twice? For the most part I didn’t have any other problems once I got the eyes and nose figured out. All the other weight painting etc seemed to go okay.

I am glad I finally got off my ass and started playing with this. I was following one video tutorial and I followed everything he did but it was a very simple rig. I started looking around and found the rigging videos on youtube by David Allen Ward and they look really thorough and more “advanced” than what I was doing. I am thinking of buying those videos and redoing my entire rig.