Physics Settings

Max linear hard snap distance.

This value represents the maximum Euclidean linear distance that will be used to extrapolate the rigid body position. Any distance beyond this value will result in the rigid body "hard snapping" to the correct position.

How much to directly lerp (linearly interpolate) to the correct position.

Generally this should be very low, if not 0.

A higher value will increase precision along with stuttering.

Useful for constraining all objects in the world, for example if you are making a 2D game using 3D environments.

You can choose from the following options:

• Full 3D
• YZ Plane
• XZ Plane
• XY Plane

If enabled, CCD (Continuous Collision Detection) will be ignored.

This is an optimization when CCD is never used, which improves performance.

Minimum relative velocity required for an object to bounce.

A typical value for simulation stability is about 0.2 * gravity.

Controls how friction is computed for multiple materials.

You can choose from the following options:

• Average
• Min
• Multiply
• Max

Restitution combine mode. Controls how restitution is computed for multiple materials.

You can choose from the following options:

• Average
• Min
• Multiply
• Max

Maximum velocity which may be used to depenetrate simulated physics objects.

This is the maximum velocity at which the Chaos physics system will correct object penetration (overlap) when a collision is detected: if a collision is detected and there is overlap, Chaos will correct the colliding object's position to be outside the object it collided with.

A value of 0 means there is no set maximum.

When creating a physics shape, the engine looks at its bounding volume and multiplies its minimum value by this multiplier.

A bigger number will generate contact points earlier, which results in higher stability at the cost of performance.

If enabled, simulate physics for this component on a dedicated server.

This should be set if simulating physics and replicating with a dedicated server.

Determines the default physics shape complexity.

You can choose from the following options:

• Project Default
• Simple And Complex
• Use Simple Collision As Complex
• Use Complex Collision As Simple

Enables persistent contact manifolds.

This will generate fewer contact points, but with more accuracy.

Reduces stability of stacking, but can help energy conservation.

Enables stabilization of contacts for slow moving bodies.

This will help improve the stability of stacking.

Defines whether to warn when physics locks are used incorrectly.

If enabled, the internal PhysX face to Unreal Engine face mapping will not be generated.

This is a memory optimization, available if you do not rely on face indices returned by scene queries.

If enabled, PhysX will not update Unreal Engine with any bodies that have moved during the simulation.

This should only be used if you have no PhysX simulation or you are manually updating the Unreal Engine data via polling PhysX.

Defines whether to disable generating KS pairs.

Enabling this makes switching between dynamic and static slower for Actors, but speeds up contact generation by early rejecting these pairs.

Defines whether to disable generating KK pairs.

Enabling this speeds up contact generation. This is required when using APEX destruction.

This is the maximum time step that a simulation can take.

If this is smaller than the tick of the engine, physics will move artificially slow in order to increase stability.

Defines whether to substep the physics simulation.

Defines whether to substep the async physics simulation.

Defines whether to tick physics simulation on an async thread.

If using async, the time step size to tick at.

Default threading model to use on module initialization.

Can be switched at runtime using p.Chaos.ThreadingModel.

You can choose from the following options:

• Task Graph
• Single Thread

The framerate / timestep ticking mode when running with a dedicated thread.

You can choose from the following options:

• Fixed
• Variable
• Variable Capped
• Variable Capped with Target

The buffering mode to use when running with a dedicated thread.

You can choose from the following options:

• Double
• Triple

During solver iterations, Unreal Engine solves each constraint in turn.

For each constraint, the engine runs the solve step CollisionPairIterations times in a row.

The number of iterations to run during the constraint fixup step.

This applies a post-solve correction that can address errors left behind during the main solver iterations.

During pushout iterations, Unreal Engine pushes out each constraint in turn.

For each constraint, the engine runs the pushout step CollisionPairIterations times in a row.

A collision margin as a fraction of size used by some boxes and convex shapes to improve collision detection results.

The core geometry of shapes that support a margin are reduced in size by the margin, and the margin is added back on during collision detection.

The net result is a shape of the same size, but with rounded corners.

An upper limit on the collision margin that will be subtracted from boxes and convex shapes.

See CollisionMarginFraction.

The maximum speed at which two bodies can be extracted from each other when they start a frame inter-penetrating.

This can happen because they spawned on top of each other, or the solver failed to fully resolve collisions last frame.

A value of zero means "no limit".

A non-zero value can be used to prevent explosive behavior when bodies start penetrating deeply.

An alternative to using this approach is to increase the number of Velocity Iterations, which is more expensive, but will ensure the bodies are depenetrated (have their penetration reduced / removed) in a single frame without explosive behavior.

The number of iterations to run during the constraint fixup step for each joint.

This applies a post-solve correction that can address errors left behind during the main solver iterations.

Cluster union connection type.

You can choose from the following options:

• Point Implicit
• Delaunay Triangulation
• Minimal Spanning Subset Delaunay Triangulation
• Point Implicit Augmented with Minimal Delaunay
• None

Triangles from triangle meshes (BSP) with an area less than or equal to this value will be removed from physics collision data.

Set this option to less than 0 to disable it.

You can have up to 62 custom physical surface types for your project.

Once you name each type, they will show up as a surface type in the physical material.