Changing pivot point of bone ? (without changing the bone)

Support Animation and Rigging
#1

Hello everyone,
I’ve changed the weight of a bone on my rig so now it’s good but the pivot point is not adaptated to the new weight. I just need to change the pivot / rotation point of this bone to be at the cursor place, without changing anything else (problem showed on image)

I know how to do it for object but couldn’t find solution for bone, someone know?
thanks!!

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I precise that moving the bone in Edit mode to change his origin is displacing the bone and so the arm too, that’s a problem. I just want the rotation point to change

#2

AFAIK changing the bone in edit mode should not give you any trouble.

#3

It should be possible to simply move the bone head without problem. Of course any existing animation will be affected by this, and possibly some constraints will behave differently (anything in world space).

#4

I recorded the problem generated by changing the bone in edit mode : https://drive.google.com/file/d/1-Ao7cyl9H2XOUTQH3b8qPSoGIDDQqauE/view
In the video i move the entire bone but i precise the same thing happen when i move head only

#5

Any idea of how to do it in this case?

#6

Some constraints could be responsible for the shift. Some of them are dependent on the initial values of the edit bone so if that gets changed the constraint has to be reset. This is true for the stretch to constraint for example.

With that said, looking at that video, that looks very much like a rig that was generated by Rigify.

You really can’t edit those in the manner that you tried and more importantly you shouldn’t need to. One of the great powers of Rigify is that you can easily make changes by changing the meta-rig and regenerating the rig again.

Finding out that your pivot points are not in the perfect place is quite common and easy to solve in this manner.

It’s not impossible to edit the generated rig but it will require some advanced rigging knowledge and you will lose the ability to regenerate the rig with the meta-rig. I would strongly advise against it.

Watch this to have all your questions regarding Rigify answered: https://www.youtube.com/watch?v=-JSFcSxsaTs&list=PLdcL5aF8ZcJv68SSdwxip33M7snakl6Dx

It also seems your collarbone is out of place. It should start closer to the sternum and move towars the shoulder:

image

1 Like
#7

Hi, thanks a lot for the detailled answer. Like you say, I did a bad work on this rig only on the shoulder /arm part and constated it after finished the weight painting and post generation rig editing.
That’s why i wanted to fix it here directly without having to re-generate all and so re do the weight paint work i did after generation. Then i have my answer that it’s not possible, i’ll restart from the metarig. Thanks again!

#8

Nobody said you would have to start over with your weightpainting. :slight_smile:

You can reuse your existing weights. When you parent the mesh to the generated armature (which i’m not even sure you have to do if you regenerate an existing rig, it might work straight away) you can choose “empty weights”. This is a bit of a misnomer because it won’t create empty weights necessarily, it will just create the needed vertex groups, if they don’t already exist, and otherwise leave them alone.

So this means you probably only have to tweak the weightpainting in the clavicle/shoulder area and keep the rest as it is if its already working to your liking.

I know people don’t want to invest the time to do a bit of study but I included that Youtube playlist for a reason. It would have taught you what I am telling you here now and more. :sweat_smile:

Sometimes a little bit of patience when watching a playlist can save you a lot of time (and frustration) even though I do understand the allure of just starting and getting on with it. :wink:

#9

Hi, the problem is solved, i didn’t thought we could make these kind of things so simply with Rigify. Also i thought that when re generating the rig, it created a new one instead of directly “fixing” the current, that is great and made me gain time. It’s true that like most people i prefer learn by practizing and skipping the theory part, but i’m realising that the theory is a necessity in such complex thing like rigging, and i really want to master Rigify. I’ll definitly take an attentive look at this playlist soon, thanks again!