Game/GigLine/Source/GigLine/GigLineVehicle.cpp

@@ -3,6 +3,7 @@
 #include "ChaosVehicleWheel.h"
 #include "ChaosWheeledVehicleMovementComponent.h"
 #include "Components/SkeletalMeshComponent.h"
+#include "PhysicsEngine/BodySetup.h"
 
 // From the Blender report (Art/blender/vehicle/report.json). Kept as named constants so a
 // model change is a compile-time mismatch to fix, not a number buried in a setup call.
@@ -298,17 +299,51 @@ void AGigLineVehicle::Tick(float DeltaSeconds)
 		DriveStart = GetActorLocation();
 	}
 
+	// A real-car mass. Without it the physics asset's box takes its computed mass, and a light
+	// body under the vehicle solver is thrown around instead of settling - which is consistent
+	// with a pawn that launches itself and never creates its wheels.
+	if (!bMassSet && SettleElapsed > 0.5f)
+	{
+		if (USkeletalMeshComponent* Body = GetMesh())
+		{
+			Body->SetMassOverrideInKg(NAME_None, 1500.0f, true);
+			bMassSet = true;
+			UE_LOG(LogTemp, Warning, TEXT("GigLine vehicle: mass override 1500 kg, mass now %.0f"),
+				Body->GetMass());
+		}
+	}
+
 	// One-shot diagnostic: why zero wheels. Wheels are built in CreateVehicle(), which runs only
 	// when the physics state produced a vehicle, so the useful facts are whether the mesh is
 	// simulating and whether it carries a physics asset at all.
 	{
 		static bool bDiagnosed = false;
-		if (!bDiagnosed && SettleElapsed > 3.0f && FParse::Param(FCommandLine::Get(), TEXT("probes")))
+		if (!bDiagnosed && SettleElapsed > 1.5f && FParse::Param(FCommandLine::Get(), TEXT("probes")))
 		{
 			bDiagnosed = true;
 			USkeletalMeshComponent* Body = GetMesh();
 			const UChaosWheeledVehicleMovementComponent* Wheeled =
 				Cast<UChaosWheeledVehicleMovementComponent>(GetVehicleMovementComponent());
+			FString BoxInfo = TEXT("no-box");
+			if (Body && Body->GetBodySetup() && Body->GetBodySetup()->AggGeom.BoxElems.Num() > 0)
+			{
+				const FKBoxElem& Box = Body->GetBodySetup()->AggGeom.BoxElems[0];
+				BoxInfo = FString::Printf(TEXT("box %.0fx%.0fx%.0f centre %.0f,%.0f,%.0f"),
+					Box.X, Box.Y, Box.Z, Box.Center.X, Box.Center.Y, Box.Center.Z);
+			}
+			FString BoundsInfo = TEXT("no-bounds");
+			if (Body)
+			{
+				const FBoxSphereBounds B = Body->Bounds;
+				BoundsInfo = FString::Printf(TEXT("bounds origin %.0f,%.0f,%.0f extent %.0f,%.0f,%.0f"),
+					B.Origin.X, B.Origin.Y, B.Origin.Z, B.BoxExtent.X, B.BoxExtent.Y, B.BoxExtent.Z);
+			}
+			UE_LOG(LogTemp, Warning, TEXT("GigLine vehicle geometry: %s | %s"), *BoxInfo, *BoundsInfo);
+			{
+				const USkeletalMesh* Asset = Body ? Body->GetSkeletalMeshAsset() : nullptr;
+				UE_LOG(LogTemp, Warning, TEXT("GigLine vehicle mesh asset: %s"),
+					Asset ? *Asset->GetName() : TEXT("NONE"));
+			}
 			UE_LOG(LogTemp, Warning,
 				TEXT("GigLine vehicle diag: mesh=%d simulating=%d physasset=%s setups=%d wheels=%d "
 				     "loc=%.0f,%.0f,%.0f"),

Game/GigLine/Source/GigLine/GigLineVehicle.h

@@ -82,5 +82,6 @@ private:
 	FVector DriveStart = FVector::ZeroVector;
 
 	float SettleElapsed = 0.f;
+	bool bMassSet = false;
 	bool bSettleReported = false;
 };