"Twist" bones wreck animations...and my life.

CASINC

I asked this question on the Unreal forum so I'll just copy and paste here, too...

Seriously, this is killing me. lol. So I use Daz3d imported characters. Took forever to figure out but I got everything setup properly with the Daz to Unreal plug-in provided assets. IK, skeleton, retargeting, blah blah, all that good stuff. But retargeted (and sometime imported) animations still leave The "twist" bones a mess with a mind of there own. In Daz characters it shoulder, forearm, and thigh twist bones. 

There has to be a way to fix this, right? Because trying to keyframe fix them is a **** show that usually just makes it worse, and takes forever.

Can they be locked to the angle of the main bone, or a virtual bone? Some type of change, fix, adjustment, Something, or in the long run they are basically unusable. 

Please help! Thanks.

catmaster

There are two methods to deal with G8 / G8.1 twist bones if not using G9 which doesn't have twist bone problem:

1. Convert G8 / G8.1 skeleton in Blender to be compatible with Unreal:

> Parent abdomenLower to pelvis so that the hip bone can be deleted

> Merge Bone Weights: limb twists to bends, hip to pelvis(G8 hip bone has no weight in the body mesh, but some geografts have weights put on the hip bone, so that needs to be merged to pelvis), merge other bone weights like ponytail bones to head bone
(The Uefy2 plugin automatically merges weights for all parented meshes of the same skeleton)

> Delete hip bone and the six limb twist bones, delete any other extra bones e.g. ponytail bones, etc.

> For each mesh parented to the skeleton, delete the twist bones vertex groups: twist bones and other e.g. dForce pin

I used the Uefy2 plugin for the weight merge feature and other useful features for rig convert. I converted all my purchased G8 / G8.1 characters for my game as it completely solved the G8 / G8.1 twist bones problem.

2. How to use UE5.1 Retargeter with twist bones:

> For the IK Rig of the G8 character, add full body IK bone settings to the twist bones and set both the Rotation Stiffness and Position Stiffness to 1

Attached the IK bone settings for my converted G8 skeleton which doesn't have twist bones, because I don't have any unconverted G8 characters to demonstrate that, but it uses the same method of adding the bone settings.

CASINC

catmaster said:

There are two methods to deal with G8 / G8.1 twist bones if not using G9 which doesn't have twist bone problem:

1. Convert G8 / G8.1 skeleton in Blender to be compatible with Unreal:

> Parent abdomenLower to pelvis so that the hip bone can be deleted

> Merge Bone Weights: limb twists to bends, hip to pelvis(G8 hip bone has no weight in the body mesh, but some geografts have weights put on the hip bone, so that needs to be merged to pelvis), merge other bone weights like ponytail bones to head bone
(The Uefy2 plugin automatically merges weights for all parented meshes of the same skeleton)

> Delete hip bone and the six limb twist bones, delete any other extra bones e.g. ponytail bones, etc.

> For each mesh parented to the skeleton, delete the twist bones vertex groups: twist bones and other e.g. dForce pin

I used the Uefy2 plugin for the weight merge feature and other useful features for rig convert. I converted all my purchased G8 / G8.1 characters for my game as it completely solved the G8 / G8.1 twist bones problem.

2. How to use UE5.1 Retargeter with twist bones:

> For the IK Rig of the G8 character, add full body IK bone settings to the twist bones and set both the Rotation Stiffness and Position Stiffness to 1

Attached the IK bone settings for my converted G8 skeleton which doesn't have twist bones, because I don't have any unconverted G8 characters to demonstrate that, but it uses the same method of adding the bone settings.

I appriciate the detailed answer (that I hope I never have to resort too) but that seems to defeat the purpose of the Daz to Unreal plug-in. lol. there has to be a in house fix since the UE manny has corrective and "twist" bones and doesn't have that issue. Given the amount of assets with the plug-in I can't imagine this isn't addressed since it's such an obvious problem. But someone else mentioned it might be a ik or full body ik related issue to. So I'm looking into that.

catmaster

They indeed fixed that twist bone problem, but the fix is not inside the free bridge, customers need to buy new G9 products to avoid those problems, seems to be quite clever marketing strategy. Guess the next G10 would get rid of that hip bone and use the Unreal bone axes for better compatibility.

Richard Haseltine

catmaster said:

They indeed fixed that twist bone problem, but the fix is not inside the free bridge, customers need to buy new G9 products to avoid those problems, seems to be quite clever marketing strategy. Guess the next G10 would get rid of that hip bone and use the Unreal bone axes for better compatibility.

Changing mid-generation would have broken everything rig-related.

dave_0aa47f5a80

The DTL conversion process automatically converts the inline twist bones to leaf twist bones, thus solving the non-concentricity issues and making the converted figure compatible and optimised for UE or further editing.

 

CASINC

Welp if anyone is wondering how I solved this problem...I just locked the rotation of all the twist bones with the post processing animation BP. 

catmaster

CASINC said:

Welp if anyone is wondering how I solved this problem...I just locked the rotation of all the twist bones with the post processing animation BP. 

That's clever it solved the problem for post processing animations, but there are more issues with twist bones that need to be solved if use the unconverted G8 skeletons, e.g the IK solvers, the control rig, the physics bodies, etc. if dig more into the Unreal features, and the compatibility with store bought assets that wouldn't work with those twist bones. 

zhiheng

CASINC said:

Welp if anyone is wondering how I solved this problem...I just locked the rotation of all the twist bones with the post processing animation BP. 

Hello, can you elaborate on the solution? I am a beginner