Fix Bug #786 (#877)

Add a property to control the AGL raycast vertical offset, otherwise the aircraft can sink in ground at Trim time
JSBSim-Team · Apr 4, 2023 · 4f3c0e6 · 4f3c0e6
1 parent 96276a5
commit 4f3c0e6
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diff --git a/...mFlightDynamicsModel/Source/JSBSimFlightDynamicsModel/Private/JSBSimMovementComponent.cpp b/...mFlightDynamicsModel/Source/JSBSimFlightDynamicsModel/Private/JSBSimMovementComponent.cpp
@@ -193,7 +193,7 @@ double UJSBSimMovementComponent::GetAGLevel(const FVector& StartECEFLocation, FV
  // Compute the raycast Origin point
  FVector StartEngineLocation;
  GeoReferencingSystem->ECEFToEngine(StartECEFLocation, StartEngineLocation);
- FVector LineCheckStart = StartEngineLocation + 200 * Up; // slightly above the starting point
+ FVector LineCheckStart = StartEngineLocation + AGLThresholdMeters * 100 * Up; // slightly above the starting point
 
  // Compute the raycast end point
  // Estimate raycast length - Altitude + 5% of ellipsoid radius in case of negative altitudes

diff --git a/...BSimFlightDynamicsModel/Source/JSBSimFlightDynamicsModel/Public/JSBSimMovementComponent.h b/...BSimFlightDynamicsModel/Source/JSBSimFlightDynamicsModel/Public/JSBSimMovementComponent.h
@@ -71,6 +71,14 @@ class JSBSIMFLIGHTDYNAMICSMODEL_API UJSBSimMovementComponent : public UActorComp
  bool DrawDebug = true;
 
 
+ /**
+ * When querying for the Above Ground Level, JSBSim can throw raycasts from several points, sometimes under the StructuralFrameOrigin. 
+ * By doing that, some of them can fail if they start below the ground. This value is a vertical offset added to each AGL Query to make sure we hit the ground. 
+ * (Aircraft geometry is of course ignored during the process - 15m should be sufficient for all kind of aircrafts - Issue #786)
+ */
+ UPROPERTY(BlueprintReadWrite, EditAnywhere, Category = "Model|Settings")
+ float AGLThresholdMeters = 15;
+
  /**
  * Center of Gravity Location in Actor local frame
  */