Adding new attachment type 'SpringArmGhost'

Docs/core_sensors.md

@@ -49,6 +49,7 @@ blueprint.set_attribute('sensor_tick', '1.0')
 
 * __Rigid attachment.__ Movement is strict regarding its parent location. This is the proper attachment to retrieve data from the simulation.  
 * __SpringArm attachment.__ Movement is eased with little accelerations and decelerations. This attachment is only recommended to record videos from the simulation. The movement is smooth and "hops" are avoided when updating the cameras' positions.  
+* __SpringArmGhost attachment.__ Like the previous one but without doing the collision test, so the camera or sensor could cross walls or other geometries.  
 
 ```py
 transform = carla.Transform(carla.Location(x=0.8, z=1.7))

Docs/python_api.md

@@ -303,6 +303,8 @@ Class that defines attachment options between an actor and its parent. When spaw
 With this fixed attatchment the object follow its parent position strictly. This is the recommended attachment to retrieve precise data from the simulation.  
 - <a name="carla.AttachmentType.SpringArm"></a>**<font color="#f8805a">SpringArm</font>**  
 An attachment that expands or retracts the position of the actor, depending on its parent. This attachment is only recommended to record videos from the simulation where a smooth movement is needed. SpringArms are an Unreal Engine component so [check the UE docs](https://docs.unrealengine.com/en-US/Gameplay/HowTo/UsingCameras/SpringArmComponents/index.html) to learn more about them. <br><b style="color:red;">Warning:</b> The <b>SpringArm</b> attachment presents weird behaviors when an actor is spawned with a relative translation in the Z-axis (e.g. <code>child_location = Location(0,0,2)</code>).  
+- <a name="carla.AttachmentType.SpringArmGhost"></a>**<font color="#f8805a">SpringArmGhost</font>**  
+An attachment like the previous one but that does not make the collision test, and that means that it does not expands or retracts the position of the actor. The term **ghost** is because then the camera can cross walls and other geometries. This attachment is only recommended to record videos from the simulation where a smooth movement is needed. SpringArms are an Unreal Engine component so [check the UE docs](https://docs.unrealengine.com/en-US/Gameplay/HowTo/UsingCameras/SpringArmComponents/index.html) to learn more about them. <br><b style="color:red;">Warning:</b> The <b>SpringArm</b> attachment presents weird behaviors when an actor is spawned with a relative translation in the Z-axis (e.g. <code>child_location = Location(0,0,2)</code>).  
 
 ---
 

LibCarla/source/carla/client/detail/Client.cpp

@@ -332,13 +332,15 @@ namespace detail {
       rpc::ActorId parent,
       rpc::AttachmentType attachment_type) {
 
-      if(attachment_type == rpc::AttachmentType::SpringArm) {
+      if (attachment_type == rpc::AttachmentType::SpringArm ||
+          attachment_type == rpc::AttachmentType::SpringArmGhost)
+      {
         const auto a = transform.location.MakeSafeUnitVector(std::numeric_limits<float>::epsilon());
         const auto z = geom::Vector3D(0.0f, 0.f, 1.0f);
         constexpr float OneEps = 1.0f - std::numeric_limits<float>::epsilon();
         if (geom::Math::Dot(a, z) > OneEps) {
           std::cout << "WARNING: Transformations with translation only in the 'z' axis are ill-formed when \
-            using SprintArm attachment. Please, be careful with that." << std::endl;
+            using SpringArm or SpringArmGhost attachment. Please, be careful with that." << std::endl;
         }
       }
 

LibCarla/source/carla/rpc/AttachmentType.h

@@ -16,6 +16,7 @@ namespace rpc {
   enum class AttachmentType : uint8_t {
     Rigid,
     SpringArm,
+    SpringArmGhost,
 
     SIZE,
     INVALID

PythonAPI/carla/source/libcarla/World.cpp

@@ -198,6 +198,7 @@ void export_world() {
   enum_<cr::AttachmentType>("AttachmentType")
     .value("Rigid", cr::AttachmentType::Rigid)
     .value("SpringArm", cr::AttachmentType::SpringArm)
+    .value("SpringArmGhost", cr::AttachmentType::SpringArmGhost)
   ;
 
   enum_<cr::CityObjectLabel>("CityObjectLabel")

PythonAPI/docs/world.yml

@@ -248,6 +248,9 @@
     - var_name: SpringArm
       doc: >
         An attachment that expands or retracts the position of the actor, depending on its parent. This attachment is only recommended to record videos from the simulation where a smooth movement is needed. SpringArms are an Unreal Engine component so [check the UE docs](https://docs.unrealengine.com/en-US/Gameplay/HowTo/UsingCameras/SpringArmComponents/index.html) to learn more about them. <br><b style="color:red;">Warning:</b> The <b>SpringArm</b> attachment presents weird behaviors when an actor is spawned with a relative translation in the Z-axis (e.g. <code>child_location = Location(0,0,2)</code>).  
+    - var_name: SpringArmGhost
+      doc: >
+        An attachment like the previous one but that does not make the collision test, and that means that it does not expands or retracts the position of the actor. The term **ghost** is because then the camera can cross walls and other geometries. This attachment is only recommended to record videos from the simulation where a smooth movement is needed. SpringArms are an Unreal Engine component so [check the UE docs](https://docs.unrealengine.com/en-US/Gameplay/HowTo/UsingCameras/SpringArmComponents/index.html) to learn more about them. <br><b style="color:red;">Warning:</b> The <b>SpringArm</b> attachment presents weird behaviors when an actor is spawned with a relative translation in the Z-axis (e.g. <code>child_location = Location(0,0,2)</code>).  
     # --------------------------------------
 
   - class_name: LabelledPoint

PythonAPI/examples/automatic_control.py

@@ -596,10 +596,10 @@ class CameraManager(object):
         bound_z = 0.5 + self._parent.bounding_box.extent.z
         attachment = carla.AttachmentType
         self._camera_transforms = [
-            (carla.Transform(carla.Location(x=-2.0*bound_x, y=+0.0*bound_y, z=2.0*bound_z), carla.Rotation(pitch=8.0)), attachment.SpringArm),
+            (carla.Transform(carla.Location(x=-2.0*bound_x, y=+0.0*bound_y, z=2.0*bound_z), carla.Rotation(pitch=8.0)), attachment.SpringArmGhost),
             (carla.Transform(carla.Location(x=+0.8*bound_x, y=+0.0*bound_y, z=1.3*bound_z)), attachment.Rigid),
-            (carla.Transform(carla.Location(x=+1.9*bound_x, y=+1.0*bound_y, z=1.2*bound_z)), attachment.SpringArm),
-            (carla.Transform(carla.Location(x=-2.8*bound_x, y=+0.0*bound_y, z=4.6*bound_z), carla.Rotation(pitch=6.0)), attachment.SpringArm),
+            (carla.Transform(carla.Location(x=+1.9*bound_x, y=+1.0*bound_y, z=1.2*bound_z)), attachment.SpringArmGhost),
+            (carla.Transform(carla.Location(x=-2.8*bound_x, y=+0.0*bound_y, z=4.6*bound_z), carla.Rotation(pitch=6.0)), attachment.SpringArmGhost),
             (carla.Transform(carla.Location(x=-1.0, y=-1.0*bound_y, z=0.4*bound_z)), attachment.Rigid)]
 
         self.transform_index = 1

PythonAPI/examples/manual_control.py

@@ -1090,17 +1090,17 @@ class CameraManager(object):
 
         if not self._parent.type_id.startswith("walker.pedestrian"):
             self._camera_transforms = [
-                (carla.Transform(carla.Location(x=-2.0*bound_x, y=+0.0*bound_y, z=2.0*bound_z), carla.Rotation(pitch=8.0)), Attachment.SpringArm),
+                (carla.Transform(carla.Location(x=-2.0*bound_x, y=+0.0*bound_y, z=2.0*bound_z), carla.Rotation(pitch=8.0)), Attachment.SpringArmGhost),
                 (carla.Transform(carla.Location(x=+0.8*bound_x, y=+0.0*bound_y, z=1.3*bound_z)), Attachment.Rigid),
-                (carla.Transform(carla.Location(x=+1.9*bound_x, y=+1.0*bound_y, z=1.2*bound_z)), Attachment.SpringArm),
-                (carla.Transform(carla.Location(x=-2.8*bound_x, y=+0.0*bound_y, z=4.6*bound_z), carla.Rotation(pitch=6.0)), Attachment.SpringArm),
+                (carla.Transform(carla.Location(x=+1.9*bound_x, y=+1.0*bound_y, z=1.2*bound_z)), Attachment.SpringArmGhost),
+                (carla.Transform(carla.Location(x=-2.8*bound_x, y=+0.0*bound_y, z=4.6*bound_z), carla.Rotation(pitch=6.0)), Attachment.SpringArmGhost),
                 (carla.Transform(carla.Location(x=-1.0, y=-1.0*bound_y, z=0.4*bound_z)), Attachment.Rigid)]
         else:
             self._camera_transforms = [
-                (carla.Transform(carla.Location(x=-2.5, z=0.0), carla.Rotation(pitch=-8.0)), Attachment.SpringArm),
+                (carla.Transform(carla.Location(x=-2.5, z=0.0), carla.Rotation(pitch=-8.0)), Attachment.SpringArmGhost),
                 (carla.Transform(carla.Location(x=1.6, z=1.7)), Attachment.Rigid),
-                (carla.Transform(carla.Location(x=2.5, y=0.5, z=0.0), carla.Rotation(pitch=-8.0)), Attachment.SpringArm),
-                (carla.Transform(carla.Location(x=-4.0, z=2.0), carla.Rotation(pitch=6.0)), Attachment.SpringArm),
+                (carla.Transform(carla.Location(x=2.5, y=0.5, z=0.0), carla.Rotation(pitch=-8.0)), Attachment.SpringArmGhost),
+                (carla.Transform(carla.Location(x=-4.0, z=2.0), carla.Rotation(pitch=6.0)), Attachment.SpringArmGhost),
                 (carla.Transform(carla.Location(x=0, y=-2.5, z=-0.0), carla.Rotation(yaw=90.0)), Attachment.Rigid)]
 
         self.transform_index = 1

PythonAPI/examples/manual_control_carsim.py

@@ -962,10 +962,10 @@ class CameraManager(object):
         bound_y = 0.5 + self._parent.bounding_box.extent.y
         Attachment = carla.AttachmentType
         self._camera_transforms = [
-            (carla.Transform(carla.Location(x=-5.5, z=2.5), carla.Rotation(pitch=8.0)), Attachment.SpringArm),
+            (carla.Transform(carla.Location(x=-5.5, z=2.5), carla.Rotation(pitch=8.0)), Attachment.SpringArmGhost),
             (carla.Transform(carla.Location(x=1.6, z=1.7)), Attachment.Rigid),
-            (carla.Transform(carla.Location(x=5.5, y=1.5, z=1.5)), Attachment.SpringArm),
-            (carla.Transform(carla.Location(x=-8.0, z=6.0), carla.Rotation(pitch=6.0)), Attachment.SpringArm),
+            (carla.Transform(carla.Location(x=5.5, y=1.5, z=1.5)), Attachment.SpringArmGhost),
+            (carla.Transform(carla.Location(x=-8.0, z=6.0), carla.Rotation(pitch=6.0)), Attachment.SpringArmGhost),
             (carla.Transform(carla.Location(x=-1, y=-bound_y, z=0.5)), Attachment.Rigid)]
         self.transform_index = 1
         self.sensors = [

PythonAPI/examples/manual_control_chrono.py

@@ -970,10 +970,10 @@ class CameraManager(object):
         bound_y = 0.5 + self._parent.bounding_box.extent.y
         Attachment = carla.AttachmentType
         self._camera_transforms = [
-            (carla.Transform(carla.Location(x=-5.5, z=2.5), carla.Rotation(pitch=8.0)), Attachment.SpringArm),
+            (carla.Transform(carla.Location(x=-5.5, z=2.5), carla.Rotation(pitch=8.0)), Attachment.SpringArmGhost),
             (carla.Transform(carla.Location(x=1.6, z=1.7)), Attachment.Rigid),
-            (carla.Transform(carla.Location(x=5.5, y=1.5, z=1.5)), Attachment.SpringArm),
-            (carla.Transform(carla.Location(x=-8.0, z=6.0), carla.Rotation(pitch=6.0)), Attachment.SpringArm),
+            (carla.Transform(carla.Location(x=5.5, y=1.5, z=1.5)), Attachment.SpringArmGhost),
+            (carla.Transform(carla.Location(x=-8.0, z=6.0), carla.Rotation(pitch=6.0)), Attachment.SpringArmGhost),
             (carla.Transform(carla.Location(x=-1, y=-bound_y, z=0.5)), Attachment.Rigid)]
         self.transform_index = 1
         self.sensors = [

PythonAPI/examples/rss/manual_control_rss.py

@@ -291,7 +291,7 @@ class Camera(object):
         bp.set_attribute('image_size_x', str(display_dimensions[0]))
         bp.set_attribute('image_size_y', str(display_dimensions[1]))
         self.sensor = self._parent.get_world().spawn_actor(bp, carla.Transform(carla.Location(
-            x=-5.5, z=2.5), carla.Rotation(pitch=8.0)), attach_to=self._parent, attachment_type=carla.AttachmentType.SpringArm)
+            x=-5.5, z=2.5), carla.Rotation(pitch=8.0)), attach_to=self._parent, attachment_type=carla.AttachmentType.SpringArmGhost)
 
         # We need to pass the lambda a weak reference to self to avoid
         # circular reference.

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Util/ActorAttacher.cpp

@@ -51,6 +51,48 @@ static void UActorAttacher_AttachActorsWithSpringArm(
   ChildComp->RegisterComponent();
 }
 
+static void UActorAttacher_AttachActorsWithSpringArmGhost(
+    AActor *Child,
+    AActor *Parent)
+{
+  auto SpringArm = NewObject<USpringArmComponent>(Parent);
+
+  // Child location negated to compensate for the spring arm rotation (rotated
+  // from the "other end" of the arm).
+  const auto ChildLocation = -Child->GetActorLocation();
+  Child->SetActorLocation(FVector::ZeroVector);
+
+  // Adding Z-offset to avoid colliding against the ground on bumpy terrain.
+  SpringArm->TargetOffset = FVector(0.0f, 0.0f, 0.0f);
+  SpringArm->bDoCollisionTest = false;
+
+  FRotator LookAt = FRotationMatrix::MakeFromX(ChildLocation).Rotator();
+  SpringArm->SetRelativeRotation(LookAt);
+  SpringArm->SetupAttachment(Parent->GetRootComponent());
+
+  SpringArm->TargetArmLength = ChildLocation.Size();
+  SpringArm->bEnableCameraRotationLag = true;
+  SpringArm->CameraRotationLagSpeed = 8.0f;
+
+  SpringArm->bInheritPitch = false;
+  SpringArm->bInheritRoll = false;
+  SpringArm->bInheritYaw = true;
+
+  SpringArm->AttachToComponent(
+      Parent->GetRootComponent(),
+      FAttachmentTransformRules::KeepRelativeTransform);
+  SpringArm->RegisterComponent();
+
+  auto ChildComp = NewObject<UChildActorComponent>(Parent);
+  ChildComp->SetupAttachment(
+      SpringArm,
+      USpringArmComponent::SocketName);
+  Child->AttachToComponent(
+      ChildComp,
+      FAttachmentTransformRules::KeepRelativeTransform);
+  ChildComp->RegisterComponent();
+}
+
 void UActorAttacher::AttachActors(
     AActor *Child,
     AActor *Parent,
@@ -67,6 +109,9 @@ void UActorAttacher::AttachActors(
     case EAttachmentType::SpringArm:
       UActorAttacher_AttachActorsWithSpringArm(Child, Parent);
       break;
+    case EAttachmentType::SpringArmGhost:
+      UActorAttacher_AttachActorsWithSpringArmGhost(Child, Parent);
+      break;
     default:
       UE_LOG(LogCarla, Fatal, TEXT("Invalid attachment type"));
   }

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Util/ActorAttacher.h

@@ -20,8 +20,9 @@ UENUM(BlueprintType)
 enum class EAttachmentType : uint8
 {
   Null = 0, // Workarround for UE4.24 issue with enums
-  Rigid      = CARLA_ENUM_FROM_RPC(Rigid)      UMETA(DisplayName = "Rigid"),
-  SpringArm  = CARLA_ENUM_FROM_RPC(SpringArm)  UMETA(DisplayName = "SpringArm"),
+  Rigid           = CARLA_ENUM_FROM_RPC(Rigid)            UMETA(DisplayName = "Rigid"),
+  SpringArm       = CARLA_ENUM_FROM_RPC(SpringArm)        UMETA(DisplayName = "SpringArm"),
+  SpringArmGhost  = CARLA_ENUM_FROM_RPC(SpringArmGhost)   UMETA(DisplayName = "SpringArmGhost"),
 
   SIZE      UMETA(Hidden),
   INVALID   UMETA(Hidden)