p.Chaos.DebugDraw.ShowExactCoreShapes

p.Chaos.DebugDraw.ShowExactCoreShapes

#Overview

name: p.Chaos.DebugDraw.ShowExactCoreShapes

This variable is created as a Console Variable (cvar).

• type: Var
• help: Whether to show the exact core shape. NOTE: Extremely expensive and should only be used on a small scene with a couple convex shapes in it

It is referenced in 3 C++ source files.

#Summary

#Usage in the C++ source code

The purpose of p.Chaos.DebugDraw.ShowExactCoreShapes is to enable the visualization of exact core shapes in the Chaos physics system’s debug drawing functionality. This setting is specifically for debugging and visualization purposes within the physics simulation.

This setting variable is primarily used in the Chaos physics system, which is an experimental physics engine in Unreal Engine 5. It’s part of the debug drawing module within Chaos.

The value of this variable is set through the Unreal Engine’s console variable system. It’s defined as an FAutoConsoleVariableRef, which allows it to be changed at runtime through console commands or configuration files.

The associated variable bChaosDebugDebugDrawExactCoreShapes directly interacts with p.Chaos.DebugDraw.ShowExactCoreShapes. They share the same value and are used interchangeably in the code.

Developers must be aware that enabling this feature is extremely expensive in terms of performance. As noted in the comment, it should only be used on a small scene with a couple of convex shapes. This is because generating the exact margin-reduced convex for each shape is a computationally intensive process.

Best practices when using this variable include:

1. Only enable it when necessary for debugging specific physics issues related to core shapes.
2. Use it in a controlled, small-scale environment to avoid performance issues.
3. Disable it immediately after use to prevent unintended performance impacts in other areas of development.
4. Consider using less expensive debug options first, such as p.Chaos.DebugDraw.ShowCoreShapes, before resorting to this exact core shape visualization.

Regarding the associated variable bChaosDebugDebugDrawExactCoreShapes:

• Its purpose is the same as p.Chaos.DebugDraw.ShowExactCoreShapes, serving as the internal boolean flag that controls the feature.
• It’s used directly in the DrawShapesImpl function to conditionally execute the exact core shape generation and visualization code.
• The value is set by the console variable system, mirroring p.Chaos.DebugDraw.ShowExactCoreShapes.
• Developers should treat it with the same caution as the console variable, understanding its performance implications.
• Best practices include using it only within the scope of the Chaos debug drawing system and not relying on it for any critical gameplay or simulation logic.

#References in C++ code

#Callsites

This variable is referenced in the following C++ source code:

#Loc: <Workspace>/Engine/Source/Runtime/Experimental/Chaos/Private/Chaos/ChaosDebugDraw.cpp:89

Scope (from outer to inner):

file
namespace    Chaos
namespace    DebugDraw

Source code excerpt:

		FAutoConsoleVariableRef CVarChaosDebugDrawConvexVertices(TEXT("p.Chaos.DebugDraw.ShowConvexVertices"), bChaosDebugDebugDrawConvexVertices, TEXT("Whether to show the vertices of convex shapes"));
		FAutoConsoleVariableRef CVarChaosDebugDrawCoreShapes(TEXT("p.Chaos.DebugDraw.ShowCoreShapes"), bChaosDebugDebugDrawCoreShapes, TEXT("Whether to show the core (margin-reduced) shape where applicable"));
		FAutoConsoleVariableRef CVarChaosDebugDrawExactShapes(TEXT("p.Chaos.DebugDraw.ShowExactCoreShapes"), bChaosDebugDebugDrawExactCoreShapes, TEXT("Whether to show the exact core shape. NOTE: Extremely expensive and should only be used on a small scene with a couple convex shapes in it"));

		bool bChaosDebugDebugDrawShowOptimizedConvexes = false;
		FAutoConsoleVariableRef CVarChaosDebugDrawShowOptimizedConvexes(TEXT("p.Chaos.DebugDraw.ShowOptimizedConvexes"), bChaosDebugDebugDrawShowOptimizedConvexes, TEXT(""));

		bool bChaosDebugDebugDrawIslands = true;
		FAutoConsoleVariableRef CVarChaosDebugDrawIslands(TEXT("p.Chaos.DebugDraw.ShowIslands"), bChaosDebugDebugDrawIslands, TEXT("Whether to show the iosland boxes when drawing islands (if you want only the contact graph)"));

#Associated Variable and Callsites

This variable is associated with another variable named bChaosDebugDebugDrawExactCoreShapes. They share the same value. See the following C++ source code.

#Loc: <Workspace>/Engine/Source/Runtime/Experimental/Chaos/Private/Chaos/ChaosDebugDraw.cpp:86

Scope (from outer to inner):

file
namespace    Chaos
namespace    DebugDraw

Source code excerpt:

		bool bChaosDebugDebugDrawConvexVertices = false;
		bool bChaosDebugDebugDrawCoreShapes = false;
		bool bChaosDebugDebugDrawExactCoreShapes = false;
		FAutoConsoleVariableRef CVarChaosDebugDrawConvexVertices(TEXT("p.Chaos.DebugDraw.ShowConvexVertices"), bChaosDebugDebugDrawConvexVertices, TEXT("Whether to show the vertices of convex shapes"));
		FAutoConsoleVariableRef CVarChaosDebugDrawCoreShapes(TEXT("p.Chaos.DebugDraw.ShowCoreShapes"), bChaosDebugDebugDrawCoreShapes, TEXT("Whether to show the core (margin-reduced) shape where applicable"));
		FAutoConsoleVariableRef CVarChaosDebugDrawExactShapes(TEXT("p.Chaos.DebugDraw.ShowExactCoreShapes"), bChaosDebugDebugDrawExactCoreShapes, TEXT("Whether to show the exact core shape. NOTE: Extremely expensive and should only be used on a small scene with a couple convex shapes in it"));

		bool bChaosDebugDebugDrawShowOptimizedConvexes = false;
		FAutoConsoleVariableRef CVarChaosDebugDrawShowOptimizedConvexes(TEXT("p.Chaos.DebugDraw.ShowOptimizedConvexes"), bChaosDebugDebugDrawShowOptimizedConvexes, TEXT(""));

		bool bChaosDebugDebugDrawIslands = true;
		FAutoConsoleVariableRef CVarChaosDebugDrawIslands(TEXT("p.Chaos.DebugDraw.ShowIslands"), bChaosDebugDebugDrawIslands, TEXT("Whether to show the iosland boxes when drawing islands (if you want only the contact graph)"));

#Loc: <Workspace>/Engine/Source/Runtime/Experimental/Chaos/Private/Chaos/ChaosDebugDraw.cpp:884

Scope (from outer to inner):

file
namespace    Chaos
namespace    DebugDraw
function     void DrawShapesImpl

Source code excerpt:

				// Generate the exact marging-reduced convex for comparison with the runtime approximation
				// Warning: extremely expensive!
				if (bChaosDebugDebugDrawExactCoreShapes)
				{
					TArray<FConvex::FVec3Type> ScaledVerts(Convex->GetVertices());
					FConvex::FVec3Type Scale(ShapeTransform.GetScale3D());
					for (FConvex::FVec3Type& Vert : ScaledVerts)
					{
						Vert *= Scale;