UMjCapsule

Capsule primitive geometry.

Unreal doesn't ship /Engine/BasicShapes/Capsule, so the visual is assembled from three engine basic shapes: a shaft cylinder and two sphere end caps. Sub-mesh transforms are kept in sync with the component's own relative scale so the gizmo still drives radius (X/Y) and half-length (Z) coherently. Caps use a Z-counter-scale so they stay spherical when the half-length differs from the radius.

Attribute	Value
Kind	Class
UE Macro	UCLASS
Inherits	UMjGeom
Blueprint Spawnable	✅ Yes

Properties Functions

Properties

Public Properties

Property	Type	Description
Radius	float	Capsule radius in MJ metres. Authored via the UE Transform's
HalfLength	float	Capsule half-length along the component's local Z axis.
VisualizerShaft	class UStaticMeshComponent*	Internal shaft cylinder.
VisualizerCapTop	class UStaticMeshComponent*	Internal top cap (positive Z).
VisualizerCapBottom	class UStaticMeshComponent*	Internal bottom cap (negative Z).
Pos	FVector
Quat	FQuat
contype	int32
conaffinity	int32
condim	int32
group	int32
priority	int32
material	FString
mass	float
density	float
solmix	float
margin	float
gap	float
hfield	FString
mesh	FString
fitscale	double
rgba	FLinearColor
verride	o
m_GeomView	GeomView	The runtime view of the MuJoCo geom. Valid only after Bind() is called.
Type	EMjGeomType
ShellInertia	EMjGeomInertia
FluidShape	EMjFluidShape
bWasImported	bool	True when this component was created via ImportFromXml. Lets export
MeshName	FString	Name of the mesh asset if Type is mesh.
bComplexMeshRequired	bool	Legacy: use complex collision mesh. Hidden — use "Decompose mesh" button instead.
CoACDThreshold	float	CoACD decomposition threshold. Lower = more accurate but more hulls. Range [0.01, 1.0].
bIsDecomposedHull	bool	True if this geom was created by CoACD decomposition of another geom.
bDisabledByDecomposition	bool	True if this geom's mesh was decomposed into hull sub-geoms.
MjClassName	FString	Optional MuJoCo class name to inherit defaults from (string fallback).
OverrideMaterial	TObjectPtr<UMaterialInterface>	Optional Unreal material override for primitive visualizer meshes (Box/Sphere/Cylinder).
DefaultClass	UMjDefault*	Reference to a UMjDefault component for default class inheritance. Hidden from the

Radius

Capsule radius in MJ metres. Authored via the UE Transform's

• Type: float
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Primitive
• Notes: Override-enabled (false)

HalfLength

Capsule half-length along the component's local Z axis.

• Type: float
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Primitive
• Notes: Override-enabled (false)

VisualizerShaft

Internal shaft cylinder.

• Type: class UStaticMeshComponent*

VisualizerCapTop

Internal top cap (positive Z).

• Type: class UStaticMeshComponent*

VisualizerCapBottom

Internal bottom cap (negative Z).

• Type: class UStaticMeshComponent*

Pos

Override-enabled (false)

• Type: FVector
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom|Spatial Pose

Quat

Override-enabled (false)

• Type: FQuat
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom|Orientation

contype

Override-enabled (bOverride_contype)

• Type: int32
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

conaffinity

Override-enabled (bOverride_conaffinity)

• Type: int32
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

condim

Override-enabled (bOverride_condim)

• Type: int32
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

group

Override-enabled (bOverride_group)

• Type: int32
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

priority

Override-enabled (bOverride_priority)

• Type: int32
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

material

Override-enabled (bOverride_material)

• Type: FString
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

mass

Override-enabled (bOverride_mass)

• Type: float
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

density

Override-enabled (bOverride_density)

• Type: float
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

solmix

Override-enabled (bOverride_solmix)

• Type: float
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

margin

Override-enabled (bOverride_margin)

• Type: float
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

gap

Override-enabled (bOverride_gap)

• Type: float
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

hfield

Override-enabled (bOverride_hfield)

• Type: FString
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

mesh

Override-enabled (bOverride_mesh)

• Type: FString
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

fitscale

Override-enabled (bOverride_fitscale)

• Type: double
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

rgba

Override-enabled (bOverride_rgba)

• Type: FLinearColor
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

verride

Override-enabled (bOverride_fluidcoef)

• Type: o
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

m_GeomView

The runtime view of the MuJoCo geom. Valid only after Bind() is called.

• Type: GeomView

Type

Override-enabled (bOverride_Type)

• Type: EMjGeomType
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

ShellInertia

Override-enabled (bOverride_ShellInertia)

• Type: EMjGeomInertia
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

FluidShape

Override-enabled (bOverride_FluidShape)

• Type: EMjFluidShape
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

bWasImported

True when this component was created via ImportFromXml. Lets export

• Type: bool

MeshName

Name of the mesh asset if Type is mesh.

• Type: FString
• Editor: 👁 VisibleAnywhere
• Blueprint: 🟢 ReadOnly
• Category: MuJoCo|Geom

bComplexMeshRequired

Legacy: use complex collision mesh. Hidden — use "Decompose mesh" button instead.

• Type: bool
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

CoACDThreshold

CoACD decomposition threshold. Lower = more accurate but more hulls. Range [0.01, 1.0].

• Type: float
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom
• Notes: Override-enabled (Type)

bIsDecomposedHull

True if this geom was created by CoACD decomposition of another geom.

• Type: bool

bDisabledByDecomposition

True if this geom's mesh was decomposed into hull sub-geoms.

• Type: bool
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

MjClassName

Optional MuJoCo class name to inherit defaults from (string fallback).

• Type: FString
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom

OverrideMaterial

Optional Unreal material override for primitive visualizer meshes (Box/Sphere/Cylinder).

• Type: TObjectPtr
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom|Visual
• Notes: Override-enabled (Type)

DefaultClass

Reference to a UMjDefault component for default class inheritance. Hidden from the

• Type: UMjDefault*
• Editor: ✏️ EditAnywhere
• Blueprint: 🔵 ReadWrite
• Category: MuJoCo|Geom
• Notes: Override-enabled (false)

Functions

Public Functions

General

Function	Returns	Description
GetVisualizerMesh()	class UStaticMeshComponent*	Returns the shaft cylinder so the overlay/debug-viz paths that grep
SyncUnrealTransformFromMj()	void	Synchronizes the Unreal Component transform (Scale/Location/Rotation)
SetGeomVisibility()	void	Sets visibility for this geom and its child visual components.
ApplyOverrideMaterial()	void	Apply a material to the visual mesh. Override in subclasses with direct member access.
GetMj()	GeomView&	Semantic accessor for raw MuJoCo data and helper methods.
GetResolvedMaterialName()	FString	Resolves the codegen-owned material FString through the default class chain. Returns empty if none found.
SizeParamsCount()	int32	Number of size parameters explicitly provided in XML.
RegisterToSpec()	void	Registers this geom to the MuJoCo spec.

GetVisualizerMesh

Returns the shaft cylinder so the overlay/debug-viz paths that grep

• Signature: GetVisualizerMesh()
• Returns: class UStaticMeshComponent*

SyncUnrealTransformFromMj

Synchronizes the Unreal Component transform (Scale/Location/Rotation)

• Signature: SyncUnrealTransformFromMj()

SetGeomVisibility

Sets visibility for this geom and its child visual components.

• Signature: SetGeomVisibility(bool bNewVisibility)

ApplyOverrideMaterial

Apply a material to the visual mesh. Override in subclasses with direct member access.

• Signature: ApplyOverrideMaterial(class UMaterialInterface* Material)

GetMj

Semantic accessor for raw MuJoCo data and helper methods.

• Signature: GetMj()
• Returns: GeomView&

GetResolvedMaterialName

Resolves the codegen-owned material FString through the default class chain. Returns empty if none found.

• Signature: GetResolvedMaterialName()
• Returns: FString

SizeParamsCount

Number of size parameters explicitly provided in XML.

• Signature: SizeParamsCount()
• Returns: int32

RegisterToSpec

Registers this geom to the MuJoCo spec.

• Signature: RegisterToSpec(class FMujocoSpecWrapper& Wrapper, mjsBody* ParentBody)

MuJoCo|Geom

Function	Returns	Description
DecomposeMesh()	void	Runs CoACD decomposition on this geom's mesh and creates persistent hull sub-geom components.
RemoveDecomposition()	void	Removes all hull sub-geoms created by decomposition and re-enables this geom.

DecomposeMesh

Runs CoACD decomposition on this geom's mesh and creates persistent hull sub-geom components.

• Signature: DecomposeMesh()
• Blueprint: 🔵 Callable

RemoveDecomposition

Removes all hull sub-geoms created by decomposition and re-enables this geom.

• Signature: RemoveDecomposition()
• Blueprint: 🔵 Callable

MuJoCo|Runtime

Function	Returns	Description
UpdateGlobalTransform()	void	Updates the Unreal SceneComponent transform to match the MuJoCo simulation state.
GetWorldLocation()	FVector	Gets the current world location from MuJoCo.
SetFriction()	void	Sets the sliding friction at runtime.

UpdateGlobalTransform

Updates the Unreal SceneComponent transform to match the MuJoCo simulation state.

• Signature: UpdateGlobalTransform()
• Blueprint: 🔵 Callable

GetWorldLocation

Gets the current world location from MuJoCo.

• Signature: GetWorldLocation()
• Blueprint: 🔵 Callable
• Returns: FVector

SetFriction

Sets the sliding friction at runtime.

• Signature: SetFriction(float NewFriction)
• Blueprint: 🔵 Callable

Private Functions

General

Function	Returns	Description
UpdateCapTransforms()	void	Position + counter-scale the caps so they sit at the shaft endpoints

UpdateCapTransforms

Position + counter-scale the caps so they sit at the shaft endpoints

• Signature: UpdateCapTransforms()