[Enhancement] Articulation Builder: QoL & UX Improvements

Source/URLab/Private/MuJoCo/Components/Actuators/MjActuator.cpp

@@ -26,6 +26,10 @@
 #include "MuJoCo/Core/MjPhysicsEngine.h"
 #include "MuJoCo/Core/MjArticulation.h"
 #include "MuJoCo/Core/Spec/MjSpecWrapper.h"
+#include "MuJoCo/Components/Joints/MjJoint.h"
+#include "MuJoCo/Components/Geometry/MjSite.h"
+#include "MuJoCo/Components/Bodies/MjBody.h"
+#include "MuJoCo/Components/Tendons/MjTendon.h"
 #include "Utils/URLabLogging.h"
 
 UMjActuator::UMjActuator()
@@ -346,3 +350,46 @@ void UMjActuator::RegisterToSpec(FMujocoSpecWrapper& Wrapper, mjsBody* ParentBod
     ExportTo(act, effectiveDefault);
 }
 
+#if WITH_EDITOR
+TArray<FString> UMjActuator::GetTargetNameOptions() const
+{
+    UClass* FilterClass = nullptr;
+    switch (TransmissionType)
+    {
+        case EMjActuatorTrnType::Joint:
+        case EMjActuatorTrnType::JointInParent:
+            FilterClass = UMjJoint::StaticClass();
+            break;
+        case EMjActuatorTrnType::Tendon:
+            FilterClass = UMjTendon::StaticClass();
+            break;
+        case EMjActuatorTrnType::Site:
+        case EMjActuatorTrnType::SliderCrank:
+            FilterClass = UMjSite::StaticClass();
+            break;
+        case EMjActuatorTrnType::Body:
+            FilterClass = UMjBody::StaticClass();
+            break;
+        default:
+            FilterClass = UMjJoint::StaticClass();
+            break;
+    }
+    return GetSiblingComponentOptions(this, FilterClass);
+}
+
+TArray<FString> UMjActuator::GetSliderSiteOptions() const
+{
+    return GetSiblingComponentOptions(this, UMjSite::StaticClass());
+}
+
+TArray<FString> UMjActuator::GetRefSiteOptions() const
+{
+    return GetSiblingComponentOptions(this, UMjSite::StaticClass());
+}
+
+TArray<FString> UMjActuator::GetDefaultClassOptions() const
+{
+    return GetSiblingComponentOptions(this, UMjDefault::StaticClass(), true);
+}
+#endif
+

Source/URLab/Private/MuJoCo/Components/Bodies/MjBody.cpp

@@ -448,3 +448,10 @@ void UMjBody::RegisterToSpec(FMujocoSpecWrapper& Wrapper, mjsBody* ParentBody)
          Setup(GetAttachParent(), ParentBody, &Wrapper);
     }
 }
+
+#if WITH_EDITOR
+TArray<FString> UMjBody::GetChildClassOptions() const
+{
+    return UMjComponent::GetSiblingComponentOptions(this, UMjDefault::StaticClass(), true);
+}
+#endif

Source/URLab/Private/MuJoCo/Components/Constraints/MjEquality.cpp

@@ -25,6 +25,9 @@
 #include "MuJoCo/Utils/MjUtils.h"
 #include "XmlNode.h"
 #include "MuJoCo/Utils/MjXmlUtils.h"
+#include "MuJoCo/Components/Bodies/MjBody.h"
+#include "MuJoCo/Components/Joints/MjJoint.h"
+#include "MuJoCo/Components/Tendons/MjTendon.h"
 #include "Utils/URLabLogging.h"
 
 UMjEquality::UMjEquality()
@@ -212,3 +215,25 @@ void UMjEquality::RegisterToSpec(FMujocoSpecWrapper& Wrapper, mjsBody* ParentBod
 
     ExportTo(Eq);
 }
+
+#if WITH_EDITOR
+TArray<FString> UMjEquality::GetObjOptions() const
+{
+    UClass* FilterClass = nullptr;
+    switch (EqualityType)
+    {
+        case EMjEqualityType::Connect:
+        case EMjEqualityType::Weld:
+            FilterClass = UMjBody::StaticClass();
+            break;
+        case EMjEqualityType::Joint:
+            FilterClass = UMjJoint::StaticClass();
+            break;
+        case EMjEqualityType::Tendon:
+            FilterClass = UMjTendon::StaticClass();
+            break;
+    }
+    if (!FilterClass) return {TEXT("")};
+    return UMjComponent::GetSiblingComponentOptions(this, FilterClass);
+}
+#endif

Source/URLab/Private/MuJoCo/Components/Defaults/MjDefault.cpp

@@ -46,6 +46,22 @@ void UMjDefault::ImportFromXml(const FXmlNode* Node)
     else ClassName = TEXT("main");
 }
 
+#if WITH_EDITOR
+void UMjDefault::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
+{
+    Super::PostEditChangeProperty(PropertyChangedEvent);
+
+    // If ClassName is empty after any edit, auto-populate from component name
+    if (ClassName.IsEmpty())
+    {
+        ClassName = GetName();
+        ClassName.ReplaceInline(TEXT("_GEN_VARIABLE"), TEXT(""));
+    }
+}
+#endif
+
+
+
 void UMjDefault::ExportTo(mjsDefault* def)
 {
     if (!def) return;

Source/URLab/Private/MuJoCo/Components/Geometry/MjGeom.cpp

@@ -21,6 +21,7 @@
 // CoACD (MIT), and libzmq (MPL 2.0). See ThirdPartyNotices.txt for details.
 
 #include "MuJoCo/Components/Geometry/MjGeom.h"
+#include "Components/StaticMeshComponent.h"
 #include "MuJoCo/Utils/MjXmlUtils.h"
 #include "MuJoCo/Utils/MjUtils.h"
 #include "MuJoCo/Utils/MjOrientationUtils.h"
@@ -508,9 +509,33 @@ void UMjGeom::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent
             UE_LOG(LogURLab, Log, TEXT("[MjGeom] User manually changed Scale for '%s'. Marking bOverride_Size = true."), *GetName());
         }
     }
+
+    // Sync MjClassName when DefaultClass changes
+    if (PropertyName == GET_MEMBER_NAME_CHECKED(UMjGeom, DefaultClass))
+    {
+        if (DefaultClass)
+            MjClassName = DefaultClass->ClassName;
+        else
+            MjClassName.Empty();
+    }
+
+    // Apply OverrideMaterial to the visual mesh
+    if (PropertyName == GET_MEMBER_NAME_CHECKED(UMjGeom, OverrideMaterial) ||
+        MemberPropertyName == GET_MEMBER_NAME_CHECKED(UMjGeom, OverrideMaterial))
+    {
+        ApplyOverrideMaterial(OverrideMaterial);
+    }
 }
 #endif
 
+void UMjGeom::ApplyOverrideMaterial(UMaterialInterface* Material)
+{
+    // Base implementation is a no-op. Mesh geoms should not have their imported
+    // materials overwritten — they already have materials from the import pipeline.
+    // Primitive subclasses (Box, Sphere, Cylinder) override this with direct
+    // VisualizerMesh access.
+}
+
 void UMjGeom::RegisterToSpec(FMujocoSpecWrapper& Wrapper, mjsBody* ParentBody)
 {
     if (!ParentBody) return;
@@ -1027,3 +1052,10 @@ void UMjGeom::RemoveDecomposition()
 void UMjGeom::DecomposeMesh() {}
 void UMjGeom::RemoveDecomposition() {}
 #endif
+
+#if WITH_EDITOR
+TArray<FString> UMjGeom::GetDefaultClassOptions() const
+{
+    return GetSiblingComponentOptions(this, UMjDefault::StaticClass(), true);
+}
+#endif

Source/URLabEditor/Public/MjGeomDetailCustomization.h → Source/URLab/Private/MuJoCo/Components/Geometry/MjMeshGeom.cpp

@@ -13,20 +13,17 @@
 // limitations under the License.
 //
 // --- LEGAL DISCLAIMER ---
-// UnrealRoboticsLab is an independent software plugin. It is NOT affiliated with, 
-// endorsed by, or sponsored by Epic Games, Inc. "Unreal" and "Unreal Engine" are 
+// UnrealRoboticsLab is an independent software plugin. It is NOT affiliated with,
+// endorsed by, or sponsored by Epic Games, Inc. "Unreal" and "Unreal Engine" are
 // trademarks or registered trademarks of Epic Games, Inc. in the US and elsewhere.
 //
-// This plugin incorporates third-party software: MuJoCo (Apache 2.0), 
+// This plugin incorporates third-party software: MuJoCo (Apache 2.0),
 // CoACD (MIT), and libzmq (MPL 2.0). See ThirdPartyNotices.txt for details.
-#pragma once
 
-#include "CoreMinimal.h"
-#include "IDetailCustomization.h"
+#include "MuJoCo/Components/Geometry/MjMeshGeom.h"
 
-class FMjGeomDetailCustomization : public IDetailCustomization
+UMjMeshGeom::UMjMeshGeom()
 {
-public:
-    static TSharedRef<IDetailCustomization> MakeInstance();
-    virtual void CustomizeDetails(IDetailLayoutBuilder& DetailBuilder) override;
-};
+	Type = EMjGeomType::Mesh;
+	bOverride_Type = true;
+}

Source/URLab/Private/MuJoCo/Components/Geometry/MjSite.cpp

@@ -232,3 +232,10 @@ void UMjSite::Bind(mjModel* model, mjData* data, const FString& Prefix)
         UE_LOG(LogURLabBind, Warning, TEXT("[MjSite] Site '%s' FAILED bind. Prefix: %s, MjName: %s"), *GetName(), *Prefix, *MjName);
     }
 }
+
+#if WITH_EDITOR
+TArray<FString> UMjSite::GetDefaultClassOptions() const
+{
+    return GetSiblingComponentOptions(this, UMjDefault::StaticClass(), true);
+}
+#endif

Source/URLab/Private/MuJoCo/Components/Geometry/Primitives/MjBox.cpp

@@ -65,6 +65,12 @@ void UMjBox::OnRegister()
         VisualizerMesh->SetupAttachment(this);
         VisualizerMesh->RegisterComponent();
     }
+
+    // Apply override material after mesh is created and registered
+    if (VisualizerMesh && OverrideMaterial && IsValid(OverrideMaterial) && GetOwner())
+    {
+        VisualizerMesh->SetMaterial(0, OverrideMaterial);
+    }
 }
 
 
@@ -115,6 +121,15 @@ void UMjBox::ExportTo(mjsGeom* geom, mjsDefault* def)
 	Super::ExportTo(geom, def);
 }
 
+void UMjBox::ApplyOverrideMaterial(UMaterialInterface* Material)
+{
+    EnsureVisualizerMesh();
+    if (VisualizerMesh && Material && IsValid(Material))
+    {
+        VisualizerMesh->SetMaterial(0, Material);
+    }
+}
+
 void UMjBox::SyncUnrealTransformFromMj()
 {
     if (m_GeomView.id == -1) return;

Source/URLab/Private/MuJoCo/Components/Geometry/Primitives/MjCylinder.cpp

@@ -65,6 +65,11 @@ void UMjCylinder::OnRegister()
         VisualizerMesh->SetupAttachment(this);
         VisualizerMesh->RegisterComponent();
     }
+
+    if (VisualizerMesh && OverrideMaterial && IsValid(OverrideMaterial) && GetOwner())
+    {
+        VisualizerMesh->SetMaterial(0, OverrideMaterial);
+    }
 }
 
 
@@ -108,6 +113,12 @@ void UMjCylinder::ExportTo(mjsGeom* geom, mjsDefault* def)
 	Super::ExportTo(geom, def);
 }
 
+void UMjCylinder::ApplyOverrideMaterial(UMaterialInterface* Material)
+{
+    EnsureVisualizerMesh();
+    if (VisualizerMesh && Material && IsValid(Material)) VisualizerMesh->SetMaterial(0, Material);
+}
+
 void UMjCylinder::SyncUnrealTransformFromMj()
 {
     if (m_GeomView.id == -1) return;

Source/URLab/Private/MuJoCo/Components/Geometry/Primitives/MjSphere.cpp

@@ -65,6 +65,11 @@ void UMjSphere::OnRegister()
         VisualizerMesh->SetupAttachment(this);
         VisualizerMesh->RegisterComponent();
     }
+
+    if (VisualizerMesh && OverrideMaterial && IsValid(OverrideMaterial) && GetOwner())
+    {
+        VisualizerMesh->SetMaterial(0, OverrideMaterial);
+    }
 }
 
 
@@ -104,6 +109,12 @@ void UMjSphere::ExportTo(mjsGeom* geom, mjsDefault* def)
 	Super::ExportTo(geom, def);
 }
 
+void UMjSphere::ApplyOverrideMaterial(UMaterialInterface* Material)
+{
+    EnsureVisualizerMesh();
+    if (VisualizerMesh && Material && IsValid(Material)) VisualizerMesh->SetMaterial(0, Material);
+}
+
 void UMjSphere::SyncUnrealTransformFromMj()
 {
     if (m_GeomView.id == -1) return;

Source/URLab/Private/MuJoCo/Components/Joints/MjJoint.cpp

@@ -512,3 +512,10 @@ FString UMjJoint::GetTelemetryTopicName() const
 {
     return FString::Printf(TEXT("joint/%s"), *GetName());
 }
+
+#if WITH_EDITOR
+TArray<FString> UMjJoint::GetDefaultClassOptions() const
+{
+    return GetSiblingComponentOptions(this, UMjDefault::StaticClass(), true);
+}
+#endif

Source/URLab/Private/MuJoCo/Components/MjComponent.cpp

@@ -25,6 +25,13 @@
 #include "MuJoCo/Components/Defaults/MjDefault.h"
 #include "MuJoCo/Components/Bodies/MjBody.h"
 
+#if WITH_EDITOR
+#include "Engine/Blueprint.h"
+#include "Engine/BlueprintGeneratedClass.h"
+#include "Engine/SimpleConstructionScript.h"
+#include "Engine/SCS_Node.h"
+#endif
+
 UMjComponent::UMjComponent()
 {
 	PrimaryComponentTick.bCanEverTick = true;
@@ -120,3 +127,47 @@ UMjDefault* UMjComponent::FindEditorDefault() const
 
     return nullptr;
 }
+
+#if WITH_EDITOR
+TArray<FString> UMjComponent::GetSiblingComponentOptions(const UObject* CallerComponent, UClass* FilterClass, bool bIncludeDefaults)
+{
+    TArray<FString> Options;
+    Options.Add(TEXT(""));  // Empty = no selection
+
+    if (!CallerComponent || !FilterClass) return Options;
+
+    // Walk the outer chain to find the owning Blueprint
+    UBlueprint* BP = nullptr;
+    for (UObject* Outer = CallerComponent->GetOuter(); Outer; Outer = Outer->GetOuter())
+    {
+        if (UBlueprintGeneratedClass* BPGC = Cast<UBlueprintGeneratedClass>(Outer))
+        {
+            BP = Cast<UBlueprint>(BPGC->ClassGeneratedBy);
+            break;
+        }
+        if (UBlueprint* Found = Cast<UBlueprint>(Outer))
+        {
+            BP = Found;
+            break;
+        }
+    }
+
+    if (!BP || !BP->SimpleConstructionScript) return Options;
+
+    for (USCS_Node* Node : BP->SimpleConstructionScript->GetAllNodes())
+    {
+        UMjComponent* MjComp = Cast<UMjComponent>(Node->ComponentTemplate);
+        if (MjComp && MjComp->IsA(FilterClass))
+        {
+            if (MjComp->bIsDefault && !bIncludeDefaults) continue;
+
+            FString DisplayName = MjComp->MjName.IsEmpty()
+                ? Node->GetVariableName().ToString()
+                : MjComp->MjName;
+            Options.Add(DisplayName);
+        }
+    }
+
+    return Options;
+}
+#endif

Source/URLab/Private/MuJoCo/Components/Physics/MjContactExclude.cpp

@@ -24,6 +24,8 @@
 #include "XmlFile.h"
 #include "mujoco/mujoco.h"
 #include "MuJoCo/Core/Spec/MjSpecWrapper.h"
+#include "MuJoCo/Components/MjComponent.h"
+#include "MuJoCo/Components/Bodies/MjBody.h"
 #include "Utils/URLabLogging.h"
 
 UMjContactExclude::UMjContactExclude()
@@ -74,3 +76,10 @@ void UMjContactExclude::Bind(mjModel* model, mjData* data, const FString& Prefix
 {
     // Contact excludes are global static data.
 }
+
+#if WITH_EDITOR
+TArray<FString> UMjContactExclude::GetBodyOptions() const
+{
+    return UMjComponent::GetSiblingComponentOptions(this, UMjBody::StaticClass());
+}
+#endif