I built the engine from source without Chaos enabled.
I then compiled with bCompileChaos=true;
I have this error
1> [308/2734] Module.GeometryCollectionEngine.cpp 1>Z:/Unreal Engine Repository/4.24/Engine/Source/Runtime/Experimental/GeometryCollectionEngine/Private/GeometryCollection/GeometryCollectionComponent.cpp(1948): error C2440: 'initializing': cannot convert from 'FPhysScene *' to 'Chaos::FPhysScene_ChaosInterface *' 1> Z:/Unreal Engine Repository/4.24/Engine/Source/Runtime/Experimental/GeometryCollectionEngine/Private/GeometryCollection/GeometryCollectionComponent.cpp(1948): note: Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast 1>Z:/Unreal Engine Repository/4.24/Engine/Source/Runtime/Experimental/GeometryCollectionEngine/Private/GeometryCollection/GeometryCollectionComponent.cpp(1949): error C2027: use of undefined type 'Chaos::FPhysScene_ChaosInterface' 1> z:\unreal engine repository\4.24\engine\source\runtime\experimental\chaossolvers\public\PBDRigidsSolver.h(64): note: see declaration of 'Chaos::FPhysScene_ChaosInterface' 1>Z:/Unreal Engine Repository/4.24/Engine/Source/Runtime/Experimental/GeometryCollectionEngine/Private/GeometryCollection/GeometryCollectionComponent.cpp(1952): error C2039: 'GetScene': is not a member of 'FPhysScene_PhysX' 1> Z:\Unreal Engine Repository\4.24\Engine\Source\Runtime\Engine\Public\Physics/PhysicsInterfaceUtils.h(11): note: see declaration of 'FPhysScene_PhysX'