p.Chaos.ImmPhys.ProjectionIterations
p.Chaos.ImmPhys.ProjectionIterations
#Overview
name: p.Chaos.ImmPhys.ProjectionIterations
This variable is created as a Console Variable (cvar).
- type:
Var - help:
Override number of projection iteration loops in immediate physics (if >= 0)
It is referenced in 3 C++ source files.
#Summary
#Usage in the C++ source code
The purpose of p.Chaos.ImmPhys.ProjectionIterations is to control the number of projection iteration loops in the immediate physics simulation within Unreal Engine 5’s Chaos physics system. This setting is specifically for the immediate physics mode, which is a part of the physics engine used for real-time simulations.
This setting variable is primarily used by the Chaos physics subsystem within Unreal Engine 5, particularly in the immediate physics simulation module. It’s part of the Engine’s physics engine implementation.
The value of this variable is set through a console variable system, as evidenced by the FAutoConsoleVariableRef declaration. This allows developers to modify the value at runtime or through configuration files.
The associated variable ChaosImmediate_Evolution_ProjectionIterations interacts directly with p.Chaos.ImmPhys.ProjectionIterations. They share the same value, with the console variable acting as an interface to set the internal variable used in the physics calculations.
Developers should be aware that this variable only takes effect if its value is greater than or equal to zero. A negative value will not override the default number of projection iterations.
Best practices when using this variable include:
- Only modify it if you understand the implications on physics simulation accuracy and performance.
- Use it in conjunction with other iteration settings (position and velocity) for balanced physics solving.
- Monitor performance impacts when increasing the number of iterations.
- Consider the trade-off between simulation accuracy and computational cost.
Regarding the associated variable ChaosImmediate_Evolution_ProjectionIterations:
- Its purpose is to store the actual number of projection iterations used in the physics simulation.
- It’s used directly in the Simulate function of the ImmediatePhysics_Chaos namespace.
- Its value is set by the console variable p.Chaos.ImmPhys.ProjectionIterations.
- It interacts with other iteration variables like ChaosImmediate_Evolution_PositionIterations and ChaosImmediate_Evolution_VelocityIterations in the physics solver.
- Developers should be aware that this variable directly affects the physics simulation’s behavior and performance.
- Best practices include carefully tuning this value alongside other physics parameters for optimal simulation results.
#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:49
Scope: file
Source code excerpt:
FAutoConsoleVariableRef CVarChaosImmPhysPositionIterations(TEXT("p.Chaos.ImmPhys.PositionIterations"), ChaosImmediate_Evolution_PositionIterations, TEXT("Override number of position iteration loops in immediate physics (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysVelocityIterations(TEXT("p.Chaos.ImmPhys.VelocityIterations"), ChaosImmediate_Evolution_VelocityIterations, TEXT("Override number of velocity iteration loops in immediate physics (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysProjectionIterations(TEXT("p.Chaos.ImmPhys.ProjectionIterations"), ChaosImmediate_Evolution_ProjectionIterations, TEXT("Override number of projection iteration loops in immediate physics (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysDisableInactiveByIndex(TEXT("p.Chaos.ImmPhys.DisableInactiveByIndex"), ChaosImmediate_DisableInactiveByIndex, TEXT("Disable bodies that are no longer active based on the index, rather than just count."));
FAutoConsoleVariableRef CVarChaosImmPhysNumCollisionsPerBlock(TEXT("p.Chaos.ImmPhys.NumCollisionsPerBlock"), ChaosImmediate_Evolution_NumCollisionsPerBlock, TEXT("The number of collision in a block in the collision pool. Higher values give better cache efficieny but waste memory if you do not need that many"));
Chaos::FRealSingle ChaosImmediate_Evolution_SimSpaceCentrifugalAlpha = 1.0f;
Chaos::FRealSingle ChaosImmediate_Evolution_SimSpaceCoriolisAlpha = 0.5f;
Chaos::FRealSingle ChaosImmediate_Evolution_SimSpaceEulerAlpha = 1.0f;
#Associated Variable and Callsites
This variable is associated with another variable named ChaosImmediate_Evolution_ProjectionIterations. They share the same value. See the following C++ source code.
#Loc: <Workspace>/Engine/Source/Runtime/Engine/Private/PhysicsEngine/ImmediatePhysics/ImmediatePhysicsChaos/ImmediatePhysicsSimulation_Chaos.cpp:40
Scope: file
Source code excerpt:
int32 ChaosImmediate_Evolution_PositionIterations = -1;
int32 ChaosImmediate_Evolution_VelocityIterations = -1;
int32 ChaosImmediate_Evolution_ProjectionIterations = -1;
int32 ChaosImmediate_DisableInactiveByIndex = 1;
int32 ChaosImmediate_Evolution_NumCollisionsPerBlock = 50;
FAutoConsoleVariableRef CVarChaosImmPhysStepTime(TEXT("p.Chaos.ImmPhys.StepTime"), ChaosImmediate_Evolution_StepTime, TEXT("Override step time (if not zero)"));
FAutoConsoleVariableRef CVarChaosImmPhysNumSteps(TEXT("p.Chaos.ImmPhys.NumSteps"), ChaosImmediate_Evolution_NumSteps, TEXT("Override num steps (if not zero)"));
FAutoConsoleVariableRef CVarChaosImmPhysInitialStepTime(TEXT("p.Chaos.ImmPhys.InitialStepTime"), ChaosImmediate_Evolution_InitialStepTime, TEXT("Initial step time (then calculated from rolling average)"));
FAutoConsoleVariableRef CVarChaosImmPhysDeltaTimeCount(TEXT("p.Chaos.ImmPhys.DeltaTimeCount"), ChaosImmediate_Evolution_DeltaTimeCount, TEXT("The number of ticks over which the moving average is calculated"));
FAutoConsoleVariableRef CVarChaosImmPhysPositionIterations(TEXT("p.Chaos.ImmPhys.PositionIterations"), ChaosImmediate_Evolution_PositionIterations, TEXT("Override number of position iteration loops in immediate physics (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysVelocityIterations(TEXT("p.Chaos.ImmPhys.VelocityIterations"), ChaosImmediate_Evolution_VelocityIterations, TEXT("Override number of velocity iteration loops in immediate physics (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysProjectionIterations(TEXT("p.Chaos.ImmPhys.ProjectionIterations"), ChaosImmediate_Evolution_ProjectionIterations, TEXT("Override number of projection iteration loops in immediate physics (if >= 0)"));
FAutoConsoleVariableRef CVarChaosImmPhysDisableInactiveByIndex(TEXT("p.Chaos.ImmPhys.DisableInactiveByIndex"), ChaosImmediate_DisableInactiveByIndex, TEXT("Disable bodies that are no longer active based on the index, rather than just count."));
FAutoConsoleVariableRef CVarChaosImmPhysNumCollisionsPerBlock(TEXT("p.Chaos.ImmPhys.NumCollisionsPerBlock"), ChaosImmediate_Evolution_NumCollisionsPerBlock, TEXT("The number of collision in a block in the collision pool. Higher values give better cache efficieny but waste memory if you do not need that many"));
Chaos::FRealSingle ChaosImmediate_Evolution_SimSpaceCentrifugalAlpha = 1.0f;
Chaos::FRealSingle ChaosImmediate_Evolution_SimSpaceCoriolisAlpha = 0.5f;
Chaos::FRealSingle ChaosImmediate_Evolution_SimSpaceEulerAlpha = 1.0f;
#Loc: <Workspace>/Engine/Source/Runtime/Engine/Private/PhysicsEngine/ImmediatePhysics/ImmediatePhysicsChaos/ImmediatePhysicsSimulation_Chaos.cpp:867
Scope (from outer to inner):
file
namespace ImmediatePhysics_Chaos
function void FSimulation::Simulate
Source code excerpt:
ChaosImmediate_Evolution_PositionIterations,
ChaosImmediate_Evolution_VelocityIterations,
ChaosImmediate_Evolution_ProjectionIterations);
FPBDJointSolverSettings JointsSettings = Implementation->Joints.GetSettings();
JointsSettings.SwingTwistAngleTolerance = ChaosImmediate_Joint_SwingTwistAngleTolerance;
JointsSettings.PositionTolerance = ChaosImmediate_Joint_PositionTolerance;
JointsSettings.AngleTolerance = ChaosImmediate_Joint_AngleTolerance;
JointsSettings.MinParentMassRatio = ChaosImmediate_Joint_MinParentMassRatio;