p.Chaos.ImmPhys.Collision.Enabled
p.Chaos.ImmPhys.Collision.Enabled
#Overview
name: p.Chaos.ImmPhys.Collision.Enabled
This variable is created as a Console Variable (cvar).
- type:
Var - help:
Enable/Disable collisions in Immediate Physics.
It is referenced in 4 C++ source files.
#Summary
#Usage in the C++ source code
The purpose of p.Chaos.ImmPhys.Collision.Enabled is to enable or disable collisions in the Immediate Physics system within Unreal Engine’s Chaos physics engine.
This setting variable is primarily used in the Immediate Physics simulation module of the Chaos physics engine, which is part of Unreal Engine’s physics system.
The value of this variable is set through a console variable, as seen in the code snippet where it’s associated with ChaosImmediate_Collision_Enabled using FAutoConsoleVariableRef. This allows for runtime modification of the collision behavior.
The associated variable ChaosImmediate_Collision_Enabled directly interacts with p.Chaos.ImmPhys.Collision.Enabled. It’s initialized with a value of 1, indicating that collisions are enabled by default.
Developers must be aware that this variable controls a fundamental aspect of the physics simulation. Disabling collisions can significantly alter the behavior of physics objects in the game.
Best practices when using this variable include:
- Only disable collisions when absolutely necessary, as it can lead to unrealistic physics behavior.
- If disabling collisions, ensure that other systems (like gameplay logic) are prepared to handle objects passing through each other.
- Use this setting for debugging or specific gameplay scenarios where collision-free movement is required.
Regarding the associated variable ChaosImmediate_Collision_Enabled:
- Its purpose is to store the enabled/disabled state of collisions in the Immediate Physics system.
- It’s used within the Chaos physics engine’s Immediate Physics simulation module.
- Its value is set at initialization to 1 (enabled) and can be modified at runtime through the console variable.
- It directly interacts with p.Chaos.ImmPhys.Collision.Enabled and is used in the Simulate function to set whether collisions are enabled in the physics simulation.
- Developers should be aware that modifying this variable will directly affect the physics simulation’s collision behavior.
- Best practices include using this variable in conjunction with the console command for debugging and ensuring that any changes to it are reverted when normal physics behavior is required.
#References in C++ code
#Callsites
This variable is referenced in the following C++ source code:
#Loc: <Workspace>/Engine/Source/Runtime/Engine/Private/PhysicsEngine/ImmediatePhysics/ImmediatePhysicsChaos/ImmediatePhysicsSimulation_Chaos.cpp:79
Scope: file
Source code excerpt:
int32 ChaosImmediate_Collision_DeferNarrowPhase = 1;
int32 ChaosImmediate_Collision_UseManifolds = 0;
FAutoConsoleVariableRef CVarChaosImmPhysCollisionDisable(TEXT("p.Chaos.ImmPhys.Collision.Enabled"), ChaosImmediate_Collision_Enabled, TEXT("Enable/Disable collisions in Immediate Physics."));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionPriority(TEXT("p.Chaos.ImmPhys.Collision.Priority"), ChaosImmediate_Collision_Priority, TEXT("Set the Collision constraint sort order (Joints have priority 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionCullDistance(TEXT("p.Chaos.ImmPhys.Collision.CullDistance"), ChaosImmediate_Collision_CullDistance, TEXT("Set the collision CullDistance (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionMaxDepenetrationVelocity(TEXT("p.Chaos.ImmPhys.Collision.MaxDepenetrationVelocity"), ChaosImmediate_Collision_MaxDepenetrationVelocity, TEXT("Set the collision Max Depenetration Velocity (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionRestitutionThresholdMultiplier(TEXT("p.Chaos.ImmPhys.Collision.RestitutionThresholdMultiplier"), ChaosImmediate_Collision_RestitutionThresholdMultiplier, TEXT("Collision Restitution Threshold (Acceleration) = Multiplier * Gravity"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionRestitutionEnabled(TEXT("p.Chaos.ImmPhys.Collision.RestitutionEnabled"), ChaosImmediate_Collision_RestitutionEnabled, TEXT("Collision Restitution Enable/Disable"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionDeferNarrowPhase(TEXT("p.Chaos.ImmPhys.Collision.DeferNarrowPhase"), ChaosImmediate_Collision_DeferNarrowPhase, TEXT("[Legacy Solver] Create contacts for all broadphase pairs, perform NarrowPhase later."));
#Associated Variable and Callsites
This variable is associated with another variable named ChaosImmediate_Collision_Enabled. They share the same value. See the following C++ source code.
#Loc: <Workspace>/Engine/Source/Runtime/Engine/Private/PhysicsEngine/ImmediatePhysics/ImmediatePhysicsChaos/ImmediatePhysicsSimulation_Chaos.cpp:67
Scope: file
Source code excerpt:
FAutoConsoleVariableRef CVarChaosImmPhysFixedStepTolerance(TEXT("p.Chaos.ImmPhys.FixedStepTolerance"), ChaosImmediate_Evolution_FixedStepTolerance, TEXT("Time remainder required to add a new step (fraction of FixedStepTime)"));
int32 ChaosImmediate_Collision_Enabled = 1;
int32 ChaosImmediate_Collision_NumPositionFrictionIterations = 0; // No static friction for RBAN
int32 ChaosImmediate_Collision_NumVelocityFrictionIterations = 1; // Dynamic friction for RBAN in velocity solve
int32 ChaosImmediate_Collision_NumPositionShockPropagationIterations = 0;
int32 ChaosImmediate_Collision_NumVelocityShockPropagationIterations = 0;
int32 ChaosImmediate_Collision_Priority = 1;
Chaos::FRealSingle ChaosImmediate_Collision_CullDistance = -1.0f;
#Loc: <Workspace>/Engine/Source/Runtime/Engine/Private/PhysicsEngine/ImmediatePhysics/ImmediatePhysicsChaos/ImmediatePhysicsSimulation_Chaos.cpp:79
Scope: file
Source code excerpt:
int32 ChaosImmediate_Collision_DeferNarrowPhase = 1;
int32 ChaosImmediate_Collision_UseManifolds = 0;
FAutoConsoleVariableRef CVarChaosImmPhysCollisionDisable(TEXT("p.Chaos.ImmPhys.Collision.Enabled"), ChaosImmediate_Collision_Enabled, TEXT("Enable/Disable collisions in Immediate Physics."));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionPriority(TEXT("p.Chaos.ImmPhys.Collision.Priority"), ChaosImmediate_Collision_Priority, TEXT("Set the Collision constraint sort order (Joints have priority 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionCullDistance(TEXT("p.Chaos.ImmPhys.Collision.CullDistance"), ChaosImmediate_Collision_CullDistance, TEXT("Set the collision CullDistance (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionMaxDepenetrationVelocity(TEXT("p.Chaos.ImmPhys.Collision.MaxDepenetrationVelocity"), ChaosImmediate_Collision_MaxDepenetrationVelocity, TEXT("Set the collision Max Depenetration Velocity (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionRestitutionThresholdMultiplier(TEXT("p.Chaos.ImmPhys.Collision.RestitutionThresholdMultiplier"), ChaosImmediate_Collision_RestitutionThresholdMultiplier, TEXT("Collision Restitution Threshold (Acceleration) = Multiplier * Gravity"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionRestitutionEnabled(TEXT("p.Chaos.ImmPhys.Collision.RestitutionEnabled"), ChaosImmediate_Collision_RestitutionEnabled, TEXT("Collision Restitution Enable/Disable"));
FAutoConsoleVariableRef CVarChaosImmPhysCollisionDeferNarrowPhase(TEXT("p.Chaos.ImmPhys.Collision.DeferNarrowPhase"), ChaosImmediate_Collision_DeferNarrowPhase, TEXT("[Legacy Solver] Create contacts for all broadphase pairs, perform NarrowPhase later."));
#Loc: <Workspace>/Engine/Source/Runtime/Engine/Private/PhysicsEngine/ImmediatePhysics/ImmediatePhysicsChaos/ImmediatePhysicsSimulation_Chaos.cpp:906
Scope (from outer to inner):
file
namespace ImmediatePhysics_Chaos
function void FSimulation::Simulate
Source code excerpt:
Implementation->Collisions.SetRestitutionEnabled(ChaosImmediate_Collision_RestitutionEnabled != 0);
Implementation->Collisions.SetRestitutionThreshold(ChaosImmediate_Collision_RestitutionThresholdMultiplier * InGravity.Size());
Implementation->Collisions.SetCollisionsEnabled(ChaosImmediate_Collision_Enabled != 0);
Implementation->Evolution.SetConstraintContainerPriority(Implementation->Collisions.GetContainerId(), ChaosImmediate_Collision_Priority);
FCollisionDetectorSettings DetectorSettings = Implementation->Collisions.GetDetectorSettings();
DetectorSettings.bAllowManifoldReuse = false;
DetectorSettings.bDeferNarrowPhase = (ChaosImmediate_Collision_DeferNarrowPhase != 0);;