View Full Version : Head direction null messes up rig

04-13-2010, 01:37 PM
Hey LWers,

I have this semi simple rig Im working on for a character. Ive made some nulls to control where the eyes and head point to.
My idea was to create a small head directional bone to always point at the head directional null, so that by moving the null, the head would move around.

Everything was going smoothly until I created the head directional bone, whose target item is the head direction null.
The issue I have is that the head bone is a child of this head directional bone and its causing the head geometry to move out of sync with the head bones and rig. Ive included a screen shot to help illustrate my point.

Ive tried changing the head directional bone's target item to none, but it doesnt snap the head back into position. Ive even tried deleting the bone and the null but the head still points downwards. Im guessing its because the head directional bone is set to point at the null, but I cant get it all realigned.

Since the head geometry is moved away from the rig, the eye bones are no longer centered in the eyes so they rotate out of the head..not good.

Hopefully I didnt make this extremely confusing..:confused:
If anyone knows where I went wrong, any help would be greatly appreciated!

04-13-2010, 01:54 PM
Ive attached another image. This is what the it should look like. I turned the bones off and the head snaps into the correct place.
Cant quite figure out how to get around this problem :grumpy:

04-13-2010, 02:06 PM
I think you just need to record rest position again. Select your (head bone) and hit 'r'. ALSO select your (head directional bone) and hit 'r'. Then uncheck your (head directional bone), so it won't effect the deformations.

After this, if your eye bones aren't lining up you need to determine which is wrong. Are the bones in the wrong spot for the eye or is the geometry being deformed by something pulling it away from the eye bone. You can disable deformations to test the 2nd theory. This is found in the 'setup' tab. If indeed your bones are not located in the correct position, just grab your head bone, disable deformations, rotate it until it's where it should be, hit 'r' on it, and re-enable deformations.

Let me know if that helps or spawns new problems. Also, I would consider not using a target for the head orientation. I could just imagine trying to animate that null around.. Instead you may consider using point constraint or even better, the position item under motion options. Basically it's similar to targeting the null, but instead of animating your null's position you'll animate rotation on the head, however your head won't rotate when you rotate the neck, it'll stay upright until you animate that head bone. I can tell you how to set it up if you are interested.

I don't do a whole lot of character animation, so others may say different, and hey maybe targeting a null with the head is the new thing, I dunno.

04-13-2010, 02:09 PM
Responding to your second post. I'm fairly positive you just need to record rest position again. Either on the new bones or bones you just edited. If you still see something change between bones on or off, then do the entire rig. Just remember to disable any bones again that you don't want deforming the rig, but it is important that those bones get rested too. Recording rest position automatically enables any selected bones, just as a note.

04-13-2010, 02:33 PM
I just had a thought about your bone placement.. I looks like your head rotation may be a little low to look natural. I think heads rotate from more just below/behind the ear. This is just a thought.

Also put in there how I would orient the head bone, and how I would choose to track a bone's position, so you can animate with rotation instead of null position. If you use your targeting rig, then the orientation of the head bone isn't all that important I guess, but it's placement still is.

See attached image.

04-13-2010, 03:06 PM
I think, 4dartist, you are a genius sir.
It was just a simple matter of recording the rest position for the head bone and and head directional bone. Once I did that and turned the bones back on, the head remained in the correct position and the eyes pivot properly inside the eye sockets. Thanks for the help, greatly appreciated.

Ill have to keep your suggested head rig in mind, itll have better deformation than my current rig.

Im going to add your suggestions to my notes on rigging, because Im sure later on down the road Ill probably over look this same problem at some point :P