Physics control component goes fully into ragdoll

Development Character & Animation
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1

This question was created in reference to: [Physics Control Component Not Properly Respecting [Content removed]

We’re trying to use physics control component following the content examples, same as the linked question.

In our case the simulated bones go fully into ragdoll and the controls don’t seem to do anything. I’m finding it difficult to figure out where it fails. I’ve seen that UPhysicsControlComponent::ApplyControl does set valid target values to the constraint instance.

I also suspected there could be issues with tick order, so I added a few logs with the frame number:

```

[2025.08.21-17.20.15:620][439]LogTemp: Display: [5439] - SkeletalMeshComponent::TickComponent PrePhysics tick BEGIN

[2025.08.21-17.20.15:620][439]LogTemp: Display: [5439] - UMainAnimInstance::NativeUpdateAnimation

[2025.08.21-17.20.15:621][439]LogTemp: Display: [5439] - SkeletalMeshComponent::TickComponent PrePhysics tick END

[2025.08.21-17.20.15:622][439]LogTemp: Display: [5439] - UMainAnimInstance::PostUpdateAnimation

[2025.08.21-17.20.15:622][439]LogTemp: Display: [5439] - UPhysicsControlComponent::TickComponent BEGIN

[2025.08.21-17.20.15:623][439]LogTemp: Display: [5439] - UPhysicsControlComponent::TickComponent END

[2025.08.21-17.20.15:624][439]LogTemp: Display: [5439] - DuringPhysics begin

[2025.08.21-17.20.15:624][439]LogTemp: Display: [5439] - DuringPhysics end

[2025.08.21-17.20.15:625][439]LogTemp: Display: [5439] - SkeletalMeshComponentEndPhysicsTickFunction::ExecuteTick BEGIN

[2025.08.21-17.20.15:625][439]LogTemp: Display: [5439] - USkeletalMeshComponent::EndPhysicsTickComponent

[2025.08.21-17.20.15:625][439]LogTemp: Display: [5439] - USkeletalMeshComponent::BlendInPhysicsInternal

[2025.08.21-17.20.15:625][439]LogTemp: Display: [5439] - SkeletalMeshComponentEndPhysicsTickFunction::ExecuteTick END

```

Which all seem to match the expected workflow.

Are there any other pointers or debug draw commands that we can explore to figure out why controls are not driving the bodies towards the animated pose?

2

The problem was that some gameplay systems could set the mesh to NoCollision, which would invalidate the list of Bodies in the skeletal mesh component. This renders the phys control records invalid so when they try applying controls to chaos it fails to find the bodies.

3

Hi, sorry that it’s taken a while to follow up on this. It bounced around between a few people on our side. Good to hear that you managed to figure out the problem.

There is a known issue with PCC controls: if you simulate and at some point set NoCollision, then later go back to one of the other collision presets, the controls are invalidated, so you end up just fully simulating them. Does that sound like the problem that you were running into?