Slight Difference in Pose Mode

I’m in the final cleanup stage for this model, getting all the weights balanced and making sure there are enough loops in just the right places on the mesh, and all that. I want a body rig done that I can reuse for some other characters, before I do all the shape keys for the face, so I need this one clean enough to reuse without discovering bugs.

The problem is that I’ve just realized that the left arm pops up the scale equivalent of about two inches when in pose mode. Everything stays in line; it just rotates with the hand dislocating the furthest. It looks perfectly natural, as the generic spread-arms pose goes, but it’s just…weird. In edit mode on the mesh, the hand is out of line with its bones. In edit mode on the armature, everything lines up just fine. It seems that in pose mode, something is pulling up on the end of the arm. All the constraints are the same on left and right, so I just don’t see why this is happening.

I still need to run Feelgoodcomics’s script to clean the weight painting, since there are lots of places with more than 100% weight between two or three bones, but I don’t think this is what’s causing the problem. Otherwise, it would be happening all over the place instead of just that one arm. I’m just not sure what I’ve done.



jackstonecleanup.blend (958 KB)

The left shoulder bone on Bone Layer 4 has rotation values. Just zero them out, and it should be fine. :yes:

Also, I am curious why you are using overlapping targetless IK solvers on the arms? What does that allow you to do?

The script allows you to normalize if you want to, but also not to if you don’t. If your weights aren’t normalized they just won’t be balanced as they appear to be, but will instead normalize themselves internally. The mesh will never move from weight painting (unless the bones are not in their home position). I also did an update on the script to version 1.1 by the way, just so you know.

That is a very good character! I look forward to seeing it complete! :smiley:

Yeah what feelgood said, just unlock them and zero them out.

I’d also like to voice interest in the results of this rigging style.

I haven’t deviated from the conventional 2-bone-chain ik, with fk switches - because it seems ik chains interpolate less predictably as they get longer. But I’m all for new approaches; I think Blender can now put multiple ik constraints on the same bone/bone chain, which is a recent development ( I think 8 months ago ).

Ah, I see it. Weird, I locked the rotation after knocking it out of alignment. How on earth didn’t I see that when I did it in the first place? I guess you can only stare at your own work long enough before you can’t really see any of it.

I figured the weights couldn’t be it, because that just doesn’t make sense. Still, I’ve got a lot of spots that are red on two bones, so I want to make sure that gets fixed, even if just for the sake of making it pretty. Also, I’ve just discovered that some vertex groups on the left hand are jumbled. Several bones are handling other bones’ areas. That’s ok though, because that hand was done first, before I knew what I was doing. Better to redo it to match the right hand anyway.

There are more targetless IK bones than there should be. One of the items on my list of cleanup duties. However, in general, the lower arm will be targetless because I will use fk most of the time, but for the ocassional pose, I’ll want to use IK, and I really don’t want to bother with setting up a switch. The reach bone (the little arrow behind each hand) is going to be used for blocking some extreme action hero poses like wild punches or leaping grabs. It basically allows me to grab him and yank him way out of alignment quickly, so that when I iron out the pose, it gets there a little more organically, less…posed. The targetless bone in the wrist…I think that was an accident. I can’t remember why I would have done that, and don’t see any advantage to it. That bone really is just for the wrist’s rotation.

I’ve also still got to get the shoulder deformations to look right. The rotation upward on the arm looks ok, but rotating it forward stretches the vest way too far in the back. I might have to use a shape key to repair that, but I’d really rather not.


Setting up a basic IK/FK switch is probably less difficult than I’m thinking you’re thinking it is :slight_smile:

It sounds like for what you want to do, using the Auto-IK feature on the armature would serve you a lot better and produce a cleaner result. When you need IK to lock the hands, just switch it on, otherwise you can animate with the Auto-IK. The coolest thing I find with the Auto-IK is you can use the mousewheel to interactively set your chain length. Really powerful stuff :slight_smile:

Understand that targetless IK will not actually work as IK - that is, it won’t lock the hands in place (there is no target to lock them to!). For a simple IK switch, you can just duplicate the arm chain, and rotation constrain each FK bone to the corresponding bone in the IK chain. Then setup the switch to turn on/off each rotation constraint. Just remember to unhook the IPO curves from the action editor by clicking the little ‘shark attack guy’ in the IPO window when setting up the driver so it works in realtime.

For the vest issue, I think it’s best to get the weight painting to work as well as possible before considering corrective shapes. I think it’s important to involve the clavicle bones as well, since when he reaches forwards and backwards, the clavicle should move quite a bit. I think it is also nice to be able to shrug and what not, and that is also done with the clavicles, which are currently locked and I don’t see another way to access them in the rig currently(?).

If I may also suggest, the current torso setup you have - with the stretchy bone in the front, seems like a weightpainting nightmare! I could be mistaken, but I don’t think such a setup is necessary. I demonstrated a simpler spine concept in the this post of the rigging thread. There are others in the examples section as well.

I would like very much to talk more about your rig, if you’re interested, since I think it has a lot of potential! If you post it in the rigging thread, we could discuss it there :yes:

Yeah, looking at it more, I think I agree. This rig is made of pieces that I liked from about 12 other rigs, so it occasionally doesn’t make sense where two related parts were adapted from unrelated rigs.

I’m trying to adapt the spine to the example now, but it’s doing weird things already, maybe because I’m not used to b-bones. When I segment the upper spine bone, the segments set up all twisted bizarrely. If I set the bezier handle numbers lower, it gets rid of that, but it also gets rid of the curvature of the spine. I can’t find much information to explain this behavior, so I ask you to make up for my lack of google powers.

Of course, I haven’t done anything to the weight painting yet, so the chest won’t actually behave properly if you try posing him. I just want to know how to set up the b-bone curvature properly first so I can get the ik chains working. Then I think I will change some of the arm functions. The more I think about it, the less I expect I’ll ever even use ik in the arms anyway, except in special cases where he’s leaning on a surface or something like that, and I can set up a special case quickly for shots like that.



jackstonespine.blend (935 KB)

Studying the work of others is a great way to learn rigging. I find studying solutions others come up with to be invaluable. Though I feel it is also important to have a clear idea of what you need your character to do, to keep things organized. If you feel IK is not necessary for the scene then you can surely add it in later, however if you know that you will need it at some point then it may make more sense just to add it in.

For the B-Bone issue, the curvature of the B-Bones are determined by their parent/child relationship (which need to be parented with ‘connected’). The top bone on Bone Layer 1 is rotated 180 degrees, so the top part of the chain is twisting 180 degrees to meet it. To fix it just roll the top bone 180 degrees in edit mode with ‘ctrl+r’.

Yeah, the problem is that the character is going to be used for a series of shorts, not all of which are planned out entirely yet, so all I know for sure is that he’ll have to do a wide range of poses without much toony squash or stretch, but that there will be some exaggerated action poses for fights and jumping off of things and so forth. Really the only time to use IK is when the tip isn’t moving, right?

Ah, bone roll, duh. Forgot about that. Much better now. Now for IK targets and weight painting. Again with the weight painting.


I should also mention that the bottom bone in the chain is actually inverted in my example. This allows for an easier swiveling of the hips (think hula hoop). I’ve not found it necessary to have 2 bones going upwards, although there is another variation on the theme that I like better which you can check out here. It allows an additional swivel from the shoulders down, but doesn’t require that you use it (making animation simpler). The result is 1 control for the hips, 1 for the chest, and an additional one for puffing the chest. Pretty much the same setup, with just the extra control. May be of interest.