Physics Constraints have no effect in Unreal 4.26

In Unreal 4.26.preview4 the physics constraints setting has no effect, while it is expected to behave like in 4.25.

constraints menu

Perhaps it is related to the announced usage of “Chaos” engine instead of PhysX.

Example project here:


The test scene contains 4 rigid-bodies falling onto a sloped plane.
They have the following constraint settings, from left to right:

  • None
  • YZPlane
  • Lock X position
  • PhysicsConstraintActor attached to this body, locking X movement and all rotations

The settings have been applied per-instance in the map.
The general intent of the constraints is to keep the body at X=0 and prevent it from sliding down the plane.

Result in 4.25

We run this map in 4.25.3 and observe the constraints preventing the bodies from sliding down the plane.

Result in 4.26

The same map run in 4.26.preview4 shows all bodies sliding the same way. The constraints have no effect.

( I have submitted the report as well )


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Hi, I don’t know if is the same problem but I have problems with physics constrains too on version 4.26.

The node “Set Linear Limit” or “Set Angular Limit” has change the “Constraint Type” to Free when I update the project to 4.26.

I just reset the “Constraint Type” to Limited (In my case) solve the problem.

I had the same problem. Updating the engine version for my project wiped our some configuration on some important blueprint nodes for physics constraint components, which caused bugs. Finding these nodes and restoring the configuration seems to have fixed the issues I was having.