Hey! I’m new to blender, but been using 3D for 15 years. I’m using Rigify and have an issue where the bones of the FK rig twist along their axes when they’re not at 90 degree angles. Please see video attached.
Hoping I’m missing something obvious here. Any help would be appreciated, thanks in advance!
Hi and welcome to the BA community. I was unable to replicate your problem can you post a link to the file?
Well, that’s one of a few problems with Rigify. People who made it thought it was a good idea to make the humerus’ rotation automatic, because in a humanoid character, it indeed makes the deformation look more natural.
If you go to the third from the right most dots, on the bottom rack (red circle), you’ll see the DEF bones layer, which is the root of the problem.
If you’re good with rigging, and you still want to fix it, do the following:
Find ‘MCH-upper_arm_tweak.L.001’ and go to its Bone Constraint Properties
You’ll find two Copy Transforms Modifiers, one with ‘upper_arm_tweak.L’ target, the other with ‘forearm_tweak.L’ target (with only 0.5 influence)
Add two Copy Location Modifiers (instead of Transforms), and set their target and influence to be exactly the same with the previous Copy Transforms
Find ‘MCH-upper_arm_tweak.L’, and add a Copy Rotation Modifier, with ‘upper_arm_fk.L’ as its target
Do the same with the right side.
Hey Sandtail, thank you for your detailed explanation and apologies on the delay. I got distracted with other facets of my game and took a LONG time to come back to this. I’m trying to replicate your steps, but every time I go to add the location modifiers I get an error saying there is “no active pose bone” selected. See attached. I know I’m probably doing something very basic incorrectly, but have been struggling with this for a couple hours and internet is not being helpful. Any light you could shed would be MUCH appreciated! Thanks in advance!
In the upper left corner, it’s the active object or bone that’s supposed to show up, not the selection. The active object is more or less the same thing as in Maya, usually the last selected. But sometimes, there isn’t one. Make sure the bone is visible and active by selecting it last.
Thanks for the reply @Hadriscus. I cannot select this bone in the viewport itself as it doesn’t show up there, only in the hierarchy. framing the selection takes me to an empty area in the general shoulder area but does not show me the bone itself. I tried messing with viewport appearance options, but no luck.
The bone has to be visible to be active (it might change in future Blender versions, but right now this is how it works). If you can still frame it, it means it’s selected, so it’s probably part of a bone layer (or bone collection, if Blender 4.0+) that’s hidden.
Thank you for the clarification @Hadriscus, Messed around with bone layers until I found the correct one and got this working. Thank you so much @Sandtail for the solve, worked like gang busters! MUCH appreciated!
Hey, I assume you’ve found the bone layer you’d need to turn on, because it’s solved! However for future reference of others who would have the same issue, in Blender version before 4.0 (3.6 and below), the MCH bone layer is here:
In Blender 4.0 and above, the bone layer has been properly reworked and it’s labeled nicely:
It’s my bad though, so I’d have to clarify, because previously I thought the MCH belonged to the DEF Bone layer! But as I checked again, it turns out, it isn’t.
Best,
Vincentius
