Pinning elbows & knees with MHX rig?
DrGonzo62
Posts: 362
Hi,
I've searched for an answer to this topic and couldn't find one.
Can you pin elbows and knees with the MHX rig? So that neither move when you transform ik hands and feet?
Looks like there's an addon to do this for Riggify, but how about MHX?
Even DAZ offers that functionality (more or less), and Maya/Motionbuilder certainly do, pinning transform and/or rotation.
I tried bone constraining them to empties, but they still move when moving the ik hands.
Any idea on how to do that?
Thanks!
Daz 3D is part of 
Connect
DAZ Productions, Inc.
7533 S Center View Ct #4664
West Jordan, UT 84084
Licensing Agreement | Terms of Service | Privacy Policy | EULA
© 2025 Daz Productions Inc. All Rights Reserved.
Comments
One way is to limit the ik chain to one bone, so it only affects the forearm, but this can't be keyframed. Otherwise afaik there's no way to pin a ik chain in blender as the ik is always computed last. Another way is to copy the bones then copy transforms from the ik chain, this way constraints can work, but this also means to modify the MHX setup.
Short answer no, MHX doesn't allow that.
https://docs.blender.org/manual/en/latest/animation/constraints/tracking/ik_solver.html
Thanks for the clarification, Padone!
It's not that big a deal, just gotten used to it over the years.
I'd rather not lose the MHX rig and its ability to use DAZ poses, even if there was another Blender rig that does allow elbows & knees pinning.
Thomas has done a really nice job with Diffeo. Very cool!
You can kind-of do it with a constraint to an empty. Anime Nyan has a tutorial about it on YouTube.
Yes, that can be done with MHX though it's not really a pin as it deforms the mesh. You enable the tweak layer then add a copy location to a empty for the knees or elbows. As I said it deforms the mesh so it's not fantastic but for small movements it may sort of work.
OK, thanks!
Yes, the deformations caused by the constraint are no good.
I'll just have to live without elbow pinning I guess.
I have to say IK targets for knees and elbows would be useful in MHX (if you turn off feet and hands of course)...
Now I think about it IK targets for knees and elbows (chains of length 1) are very difficult, i.e. a chain of 1 - there are no degrees of freedom to work with.
I frequently use that feature when working in Motionbuilder.
ARP has it natively.
For professional animation rigify certainly gets more features than MHX. It is a tradeoff, if you want to use daz poses and animations then MHX is more compatible with daz, if you want to animate in blender then rigify provides more features. For rigify there's also extensions that you can eventually setup in the metarig. Or use ARP.
GitHub - angavrilov/angavrilov-rigs: Custom Rigify rigs (feature set package)
p.s. If you go for rigify, be sure to get the latest version of diffeomorphic, as compatibility with custom metarigs has been added recently.
Diffeomorphic / import_daz / Downloads — Bitbucket
Angavrilov's feature sets GitHub - angavrilov/angavrilov-rigs: Custom Rigify rigs (feature set package) for Rigify is the way to go, especially if you're using Diffeo. Not only does it give you full control while pinned (forearms hands/shins feet stay in FK when pinning is activated and can be rotated, translated etc) it also keeps the upper chain including the hips in IK mode. It also adds a pivot point to the hip, wrists and ankle bones which gives you the ability to animate certain things almost impossible without (well without difficulty). The influence con be changed as well, and there is a 'snap to shoulder' and 'snap to hip' option to ensure FK and IK layers always line up perfectly when swithcing on off (no jittering). IMO it is better than both ARP's pinning and Blenrig's and the empty method mentioned because it never deforms the mesh when active, even when translating (dragging) the IK Mid controller. It's still not completely perfect, but it is the best pinning mechanism I've seen/used in Blender, besides creating a custom pinning mechanism from scratch. Why it isn't integrated standard with Rigify is beyond me. You do have to setup the metarig a special way to use it though, (don't worry even mocap will still work after this I use it all the time).
Special setup:
The particular feature set you need to look for for the pinning is the Body IK one.
Step1: Import character from Diffeomorphic. Generate Rigify metarig.
Step2: (Must be done 1 at a time and make sure x-symmetry is off!) Go into Edit Mode and select the head of the metarig upper arm bone. Shift-S cursor to selected. Then select the tail of the metarig shoulder bone and THEN the head of the meatrig upper arm bone with the 3d cursor on it, Shift-S selection to cursor. Do the same to other side (x symmetry needs to be off)
Step 3:Go in to Pose Mode, select metarig shoulder bone go into Bone Properties>Rigify Type and select Body IK shoulder. Select metarig upper arm bone, Bone Properties>Rigify Type and select Body IK arm. Select metarig Spine bone, Bone Properties>Rigify Type and select Body IK basic spine. Select metarig thigh bone, Bone Properties>Rigify Type and select Body IK leg.
Step 4: Make sure you check off all options for pivots and assign IK Mid collections for all bones mentioned (I put IK Mid arms on IK arms, IK Mid leg on IK leg etc).
Step 5: Finally generate Rigify rig.
All controls will be in the Rigify Main Properties panel as usual when you select the Mid IK controllers (rectangles around the limbs). Workflow would be get limbs into position of posing, snap fk or IK accordingly, then select IK Mid associated with limb, snap elbow/knee to hand/foot then put knee or elbow IK influence slider to 1 (or whatever you need). The pivot points are the empties on the wrists, ankles, and hip as mentioned and can be translated/rotated/scaled for whatever.
I have never tried rigify. I might play with it on a Daz character this weekend then.
Hey CraptinCrunch69,
Thanks for the info! I'll checked it out.
Select the pole vector/IK handle/ Whatever you wnat to call it. In this case for MHX it's the cones. Select one, then hit tab to go into edit mode. On the right side go into the Bone Properties menu. In the bone properties menu go to "Relations" and click the "x" next to the bone name in the "parent" box. Do this for both Elbow and Knee Ik Controls. Now when you move the hands or the feet these controls will stay locked in place which is typical behavior of more indutry standard rigs. This also make them animatable.
Alternatively you can select all four and use "alt + left" Click on the "x" to do it to all four rig controls at the same time.
I said something about this to Thomas a long while back and he changed it. I guess there was a regression somewhere. But it's an easy enough fix.
In the MHX options you can make the poles child of root, which I agree it is more standard. Not that the other options are not "animatable".
p.s. Anyway this has nothing to do with pinning as poles don't pin.
I mussunderstood what weas being asked. For whatever reason it read as someone using terms they think describe the action they are trying to do, not replicate.