View Full Version : Bone problem

03-25-2009, 10:43 AM
I thought I had worked through all the usual bone problems having to do with pivot rotation, weights, resting... Now I've got a new one and I can't figure it out.

I have a more or less standard rig (bi-ped). Bones were rested with charactor in seated position. Then upper extremities were posed (non-IK)in frame 10...just a test. All was well. Scene was closed out.

When I reopened scene the bones that I had positioned still worked and still assumed the pose at frame 10. But the mesh no longer follows these bones...at all. The bones that I didn't use in the initial pose still deform properly. The mesh has weights, those have not changed.

I tried reloading the scene, deleting the rig and importing a save copy, and reassigning weights.

I know I must be dealing with something elementary but I'm stumped. Any help would make my head quit hurting.

03-25-2009, 11:21 AM
Did you use the Record Pivot Rotation command?
Where did you learn this practice?

Likely you have Recorded Pivot Rotation, but omitted to Record Bone Rest Position after that. Pick any of the thread whose title matches to read more:


03-25-2009, 12:33 PM
I appreciate your reply,Dan. I've rigged a couple characters so far...not a lot but they have worked fine.

The practice that has worked for me is to lay the bones, bone twist to orient pitch, RPR to zero hpb, then rest each bone individually...Bones on, good to go.

But not this time.

03-25-2009, 12:47 PM
Then that is certainly weird. I haven't a clue what else it could be.

But if you do go back to the rest frame and rerest all bones, does the mesh not snap back in place and deform as it should? And if you save after that, will it fail on load again?

03-25-2009, 12:53 PM
Attached, the figure's arm bones are posed where the mesh should be and was when I initially set this pose. After I reopened the scene, this is what I have. These bones do not now affect the mesh at all. The rest of the bones continue to work fine with the remainder of the mesh.

Any help appreciated.

Edit: Reload,rerest changes nothing.

03-25-2009, 01:05 PM
i have recently encountered a problem like this as well. i setup my character and placed all the bones, rotated their pivots to zero them out, made them active, saved the scene and closed. when i reopened the scene my characters back looks like it is broken in half and the upper body is not responding to the rig at all. please keep us informed if you figure out what happened and i will do the same.

03-25-2009, 01:22 PM
Hmm... those arms/fingers look squashed. Might you perhaps have scaled a bone instead of changing the rest length? Scale should commonly be <1,1,1> for all bones.

03-25-2009, 01:22 PM
Can you share the rig?

03-25-2009, 01:23 PM
i have recently encountered a problem like this as well.

May I ask what you did to fix it? Probably redid bones, but I have to ask.

03-25-2009, 01:30 PM
Can you share the rig?

sure. Thanks for the assistance.

03-25-2009, 01:33 PM
i have not fixed it yet haha when i reopened it and saw it was jacked i just kinda said i will fix it later and have not reopened it yet.

i was very careful to only change the bone's length and not scale it. i learned that mistake the hard way about a year ago haha

03-25-2009, 01:46 PM
Hmm... those arms/fingers look squashed. .
Those are the arms I modeled.

03-25-2009, 02:06 PM
Attached is frame 0... bones in place in the mesh. Scaling bones is something I think you only do once by accident.

By the way, this is a huge scene with about 1mil polys). the figure you see is about 20k. The head and "feet" are attached to the green "background" that you see...one seemless mesh (don't ask). Question would be that the dimensions and quantities are making things dysfunctional?

03-25-2009, 02:58 PM
That rig file wasn't revealing anything odd. For what that's worth. I'm not sure how a rig really transfers into the rig format, how its loaded and what might transpire once its loaded (maybe it rerests on import?). Imho you should always prefer an LWS.

In any case, I created some mock geometry. Imported the rig and things work as they should. (I didn't rerest). I couldn't see anything weird about the bone setup either. So I guess it must be your weightmaps? If you remove them and rely on bone falloff alone, how do thing work out? Personally I'd try to do without the weightmaps if possible and only use them in areas really necessary. Perhaps only use them for the hand and fingers.

I haven't heard anything about high polycount botching bone deformations. But if you have items of vastly different sizes that might throw of the precision of IK when the character is far from the origin. Perhaps also deformations/displacements, but that is less likely as those work in item space, not world space.

03-25-2009, 04:39 PM
Oh, happy, happy day. It's fixed. You were right Evenflcw. The mesh responded without weights (but necessary for control.) When I redeveloped the weight maps and applied, all was well. Not sure what happened, but probably has to do with my inexperience. Thanks to all of you for your help.

Evenflcw, I need to put you on retainer. That's twice in one week you've helped me. I'll try not to bother for a while.

I look forward to the day when I can repay.

03-25-2009, 04:48 PM
Well, what do you know!
Guess enough times and eventually you'll be right! :)

This is why I visit the forum, so don't worry about it.

03-25-2009, 04:52 PM
So I guess it must be your weightmaps? If you remove them and rely on bone falloff alone, how do thing work out? Personally I'd try to do without the weightmaps if possible and only use them in areas really necessary. Perhaps only use them for the hand and fingers.

is this a new problem? i have used weight maps for quite a while and havent run into this before.

03-25-2009, 05:04 PM
I'm not sure there was a problem. Atleast not an easily repeatable one. What I wrote is just a common suggestion and practice since bone falloff can work really well, especially together with so called hold bones. It's also often faster and more flexible than setting up and using weights. This practice is perhaps most well-known as technique advocated and demonstrated by Splinegod/Larry Shultz. I might not agree with him on other matters, but on this one we agree.