Bones constraints problems (IK > Copy Transforms > Damped Track) #110435

New Issue

ertuqueque · 2023-07-24T23:58:33+02:00

ertuqueque commented

2023-07-24 23:58:33 +02:00

System Information
Operating system: Linux-6.4.3-1-MANJARO-x86_64-with-glibc2.37 64 Bits, X11 UI
Graphics card: NVIDIA GeForce GTX 1060 3GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 535.54.03

Short description of error
If there's a chain of bones (let's call it "A") that have an IK mechanism... and there's another chain of bones ("B") with "Copy Transforms" constraints to copy each of the "A" bones... and the "B" chain of bones also have a series of "Damped Track" constraints... these Damped Track constraints seem to be evaluated even if their influence is at 0 and the constraint is turned off!

(The problem magically disappears if we remove the IK constraint in the chain A)

Ideally, the Damped Track constraints in chain "B" should decrease it's effect as the influence parameter approaches 0... Even if chain "A" has an IK setup.

Exact steps for others to reproduce the error
Too complex to explain here. I attached a file with the setup:

Bone layer 1: Chain "A" with the IK constraint.
Bone layer 2: Chain "B" with the Copy Transforms and the Damped Track constraints.
Bone layer 3: Root bone and Chain "A" (IK) controller.

(The Root bone has a "swing" animation to easily show the problem).

**System Information** Operating system: Linux-6.4.3-1-MANJARO-x86_64-with-glibc2.37 64 Bits, X11 UI Graphics card: NVIDIA GeForce GTX 1060 3GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 535.54.03 **Short description of error** If there's a chain of bones (let's call it "A") that have an IK mechanism... and there's another chain of bones ("B") with "Copy Transforms" constraints to copy each of the "A" bones... and the "B" chain of bones also have a series of "Damped Track" constraints... **these Damped Track constraints seem to be evaluated even if their influence is at 0 and the constraint is turned off!** (The problem magically disappears if we remove the IK constraint in the chain A) Ideally, the Damped Track constraints in chain "B" should decrease it's effect as the influence parameter approaches 0... Even if chain "A" has an IK setup. **Exact steps for others to reproduce the error** Too complex to explain here. I attached a file with the setup: Bone layer 1: Chain "A" with the IK constraint. Bone layer 2: Chain "B" with the Copy Transforms and the Damped Track constraints. Bone layer 3: Root bone and Chain "A" (IK) controller. (The Root bone has a "swing" animation to easily show the problem).

damped_track_bug.blend

145 KiB

ertuqueque added the

labels 2023-07-24 23:58:34 +02:00

Germano Cavalcante commented

2023-07-28 02:49:56 +02:00

It's a bit tricky to understand what it's intended to do in the file
Even more so when creating dependency cycles:

Dependency cycle detected:
  OBArmature/B_bone.002/BONE_CONSTRAINTS() depends on
  OBArmature/B_bone.002/BONE_POSE_PARENT() via 'Pose -> Constraints Stack'
  OBArmature/B_bone.001/BONE_DONE() via 'Parent Bone -> Child Bone'
  OBArmature/B_bone.001/BONE_READY() via 'Ready -> Done'
  OBArmature/B_bone.001/BONE_CONSTRAINTS() via 'Constraints -> Ready'
  OBArmature/B_bone.002/BONE_DONE() via 'Damped Track'
  OBArmature/B_bone.002/BONE_READY() via 'Ready -> Done'
  OBArmature/B_bone.002/BONE_CONSTRAINTS() via 'Constraints -> Ready'
Dependency cycle detected:
  OBArmature/B_bone.003/BONE_CONSTRAINTS() depends on
  OBArmature/B_bone.003/BONE_POSE_PARENT() via 'Pose -> Constraints Stack'
  OBArmature/B_bone.002/BONE_DONE() via 'Parent Bone -> Child Bone'
  OBArmature/B_bone.002/BONE_READY() via 'Ready -> Done'
  OBArmature/B_bone.002/BONE_CONSTRAINTS() via 'Constraints -> Ready'
  OBArmature/B_bone.003/BONE_DONE() via 'Damped Track'
  OBArmature/B_bone.003/BONE_READY() via 'Ready -> Done'
  OBArmature/B_bone.003/BONE_CONSTRAINTS() via 'Constraints -> Ready'
Dependency cycle detected:
  OBArmature/B_bone.003/BONE_CONSTRAINTS() depends on
  OBArmature/B_bone.004/BONE_DONE() via 'Damped Track'
  OBArmature/B_bone.004/BONE_READY() via 'Ready -> Done'
  OBArmature/B_bone.004/BONE_CONSTRAINTS() via 'Constraints -> Ready'
  OBArmature/B_bone.004/BONE_POSE_PARENT() via 'Pose -> Constraints Stack'
  OBArmature/B_bone.003/BONE_DONE() via 'Parent Bone -> Child Bone'
  OBArmature/B_bone.003/BONE_READY() via 'Ready -> Done'
  OBArmature/B_bone.003/BONE_CONSTRAINTS() via 'Constraints -> Ready'
Detected 3 dependency cycles
WARN (bke.anim_sys): D:\BlenderDev\blender\source\blender\blenkernel\intern\anim_sys.cc:4228 BKE_animsys_eval_driver: invalid driver - cycles.preview_denoising_start_sample[0]

However, I noticed that these dependency cycles are being created even with the constraint disabled.
This makes it look like a duplicate of #105790

It's a bit tricky to understand what it's intended to do in the file Even more so when creating dependency cycles: ``` Dependency cycle detected: OBArmature/B_bone.002/BONE_CONSTRAINTS() depends on OBArmature/B_bone.002/BONE_POSE_PARENT() via 'Pose -> Constraints Stack' OBArmature/B_bone.001/BONE_DONE() via 'Parent Bone -> Child Bone' OBArmature/B_bone.001/BONE_READY() via 'Ready -> Done' OBArmature/B_bone.001/BONE_CONSTRAINTS() via 'Constraints -> Ready' OBArmature/B_bone.002/BONE_DONE() via 'Damped Track' OBArmature/B_bone.002/BONE_READY() via 'Ready -> Done' OBArmature/B_bone.002/BONE_CONSTRAINTS() via 'Constraints -> Ready' Dependency cycle detected: OBArmature/B_bone.003/BONE_CONSTRAINTS() depends on OBArmature/B_bone.003/BONE_POSE_PARENT() via 'Pose -> Constraints Stack' OBArmature/B_bone.002/BONE_DONE() via 'Parent Bone -> Child Bone' OBArmature/B_bone.002/BONE_READY() via 'Ready -> Done' OBArmature/B_bone.002/BONE_CONSTRAINTS() via 'Constraints -> Ready' OBArmature/B_bone.003/BONE_DONE() via 'Damped Track' OBArmature/B_bone.003/BONE_READY() via 'Ready -> Done' OBArmature/B_bone.003/BONE_CONSTRAINTS() via 'Constraints -> Ready' Dependency cycle detected: OBArmature/B_bone.003/BONE_CONSTRAINTS() depends on OBArmature/B_bone.004/BONE_DONE() via 'Damped Track' OBArmature/B_bone.004/BONE_READY() via 'Ready -> Done' OBArmature/B_bone.004/BONE_CONSTRAINTS() via 'Constraints -> Ready' OBArmature/B_bone.004/BONE_POSE_PARENT() via 'Pose -> Constraints Stack' OBArmature/B_bone.003/BONE_DONE() via 'Parent Bone -> Child Bone' OBArmature/B_bone.003/BONE_READY() via 'Ready -> Done' OBArmature/B_bone.003/BONE_CONSTRAINTS() via 'Constraints -> Ready' Detected 3 dependency cycles WARN (bke.anim_sys): D:\BlenderDev\blender\source\blender\blenkernel\intern\anim_sys.cc:4228 BKE_animsys_eval_driver: invalid driver - cycles.preview_denoising_start_sample[0] ``` However, I noticed that these dependency cycles are being created even with the constraint disabled. This makes it look like a duplicate of #105790

Germano Cavalcante added

Status

Needs Info from Developers

and removed

labels 2023-07-28 02:50:22 +02:00

ertuqueque commented

2023-07-29 00:58:52 +02:00

Oh, I should have been more clear about the details... I know there are some dependency cycles, but that's actually a known "trick" to create a "tail" effect with a series of damped track contraints, like this one (also, attaching the file in case you want to check).

I'm creating a cartoonish character and adding "jiggle" to some bones with this trick and it worked like a charm for the FK areas (body, wings...) Until I added this effect to the parts related to the IK limbs (legs and antennas).

Oh, I should have been more clear about the details... I know there are some dependency cycles, but that's actually a known "trick" to create a "tail" effect with a series of damped track contraints, like this one (also, attaching the file in case you want to check). I'm creating a cartoonish character and adding "jiggle" to some bones with this trick and it worked like a charm for the FK areas (body, wings...) Until I added this effect to the parts related to the IK limbs (legs and antennas).

damped_track_tail.blend

144 KiB

damped_track_tail.mp4

118 KiB

Nathan Vegdahl commented

2023-10-31 12:58:00 +01:00

I know there are some dependency cycles, but that's actually a known "trick" to create a "tail" effect with a series of damped track contraints

Using dependency cycles in rigs is not a supported use case. Rigs with dependency cycles are considered invalid, hence why Blender gives you warnings when you have them.

Can you reproduce the issue with a rig that has no dependency cycles?

> I know there are some dependency cycles, but that's actually a known "trick" to create a "tail" effect with a series of damped track contraints Using dependency cycles in rigs is not a supported use case. Rigs with dependency cycles are considered invalid, hence why Blender gives you warnings when you have them. Can you reproduce the issue with a rig that has no dependency cycles?

Germano Cavalcante added

Status

Needs Information from User

and removed

Status

Needs Info from Developers

labels 2023-10-31 13:14:16 +01:00

Pratik Borhade commented

2023-12-29 07:36:34 +01:00

No activity for more than a week. As per the tracker policy we assume the issue is gone and can be closed.

Thanks again for the report. If the problem persists please open a new report with the required information.

No activity for more than a week. As per the tracker policy we assume the issue is gone and can be closed. Thanks again for the report. If the problem persists please open a new report with the required information.

Pratik Borhade closed this issue

2023-12-29 07:36:37 +01:00

Blender Bot added

Status

Archived

and removed

Status

Needs Information from User

labels 2023-12-29 07:36:39 +01:00

Sign in to join this conversation.