UMjTendon¶
Component representing a MuJoCo tendon.
Tendons are kinematic coupling mechanisms that can:
- Connect joints (fixed tendon: uses Joint wraps with gear coefficients)
- Route through space (spatial tendon: uses Site, Geom, and Pulley wraps)
This component mirrors the <fixed> and <spatial> elements inside <tendon> in MuJoCo XML.
Attach this component directly to the AMjArticulation root (not to a body).
| Attribute | Value |
|---|---|
| Kind | Class |
| UE Macro | UCLASS |
| Inherits | UMjComponent |
| Blueprint Spawnable | ✅ Yes |
Properties¶
Public Properties¶
| Property | Type | Description |
|---|---|---|
m_TendonView |
TendonView | The runtime view of the MuJoCo tendon. Valid only after Bind() is called. |
Wraps |
TArray<FMjTendonWrap> | Ordered list of wrap entries that define the tendon path. |
MjClassName |
FString |
Optional MuJoCo default class name to inherit from. |
SpringLength |
TArray<float> |
Spring resting length [min, max]. Use (-1, -1) to compute from qpos_spring. |
FrictionLoss |
float |
Friction loss (dry friction applied along the tendon). |
Armature |
float |
Inertia associated with the tendon velocity. |
bLimited |
bool |
Whether the tendon has length limits. |
Margin |
float |
Margin for limit detection. |
bActFrcLimited |
bool |
Whether the tendon has actuator force limits. |
Width |
float |
Width for rendering the tendon (meters). |
Rgba |
FLinearColor |
Tendon color (RGBA). |
Group |
int |
Visualization group (0 = always visible). |
m_TendonView¶
The runtime view of the MuJoCo tendon. Valid only after Bind() is called.
- Type: TendonView
Wraps¶
Ordered list of wrap entries that define the tendon path.
- Type: TArray<FMjTendonWrap>
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon
MjClassName¶
Optional MuJoCo default class name to inherit from.
- Type: FString
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon
SpringLength¶
Spring resting length [min, max]. Use (-1, -1) to compute from qpos_spring.
- Type: TArray
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Physics
- Notes: Override-enabled (
bOverride_SpringLength)
FrictionLoss¶
Friction loss (dry friction applied along the tendon).
- Type: float
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Physics
- Notes: Override-enabled (
bOverride_FrictionLoss)
Armature¶
Inertia associated with the tendon velocity.
- Type: float
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Physics
- Notes: Override-enabled (
bOverride_Armature)
bLimited¶
Whether the tendon has length limits.
- Type: bool
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Limits
- Notes: Override-enabled (
bOverride_Limited)
Margin¶
Margin for limit detection.
- Type: float
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Limits
- Notes: Override-enabled (
bOverride_Margin)
bActFrcLimited¶
Whether the tendon has actuator force limits.
- Type: bool
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Limits
- Notes: Override-enabled (
bOverride_ActFrcLimited)
Width¶
Width for rendering the tendon (meters).
- Type: float
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Visual
- Notes: Override-enabled (
bOverride_Width)
Rgba¶
Tendon color (RGBA).
- Type: FLinearColor
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Visual
- Notes: Override-enabled (
bOverride_Rgba)
Group¶
Visualization group (0 = always visible).
- Type: int
- Editor: ✏️ EditAnywhere
- Blueprint: 🔵 ReadWrite
- Category: Mj Tendon|Visual
- Notes: Override-enabled (
bOverride_Group)
Functions¶
Public Functions¶
General¶
| Function | Returns | Description |
|---|---|---|
ExportTo() |
void | Exports properties to a pre-created MuJoCo spec tendon structure. |
RegisterToSpec() |
void | Registers this tendon to the MuJoCo spec. |
Bind() |
void | Binds this component to the live MuJoCo simulation. |
ImportFromXml() |
void | Imports properties from a raw XML node. |
GetMj() |
TendonView& | Semantic accessor for raw MuJoCo data and helper methods. |
GetMjName() |
FString |
Gets the full prefixed name of this tendon in the compiled MuJoCo model. |
ExportTo¶
Exports properties to a pre-created MuJoCo spec tendon structure.
- Signature:
ExportTo(mjsTendon*Tendon,mjsDefault*def)
RegisterToSpec¶
Registers this tendon to the MuJoCo spec.
- Signature:
RegisterToSpec(class FMujocoSpecWrapper& Wrapper,mjsBody*ParentBody)
Bind¶
Binds this component to the live MuJoCo simulation.
- Signature:
Bind(mjModel*model,mjData*data,const FString&Prefix)
ImportFromXml¶
Imports properties from a raw XML node.
- Signature:
ImportFromXml(const class FXmlNode*Node)
GetMj¶
Semantic accessor for raw MuJoCo data and helper methods.
- Signature:
GetMj() - Returns: TendonView&
GetMjName¶
Gets the full prefixed name of this tendon in the compiled MuJoCo model.
- Signature:
GetMjName() - Returns: FString
MuJoCo|Runtime¶
| Function | Returns | Description |
|---|---|---|
GetLength() |
float |
Gets the current tendon length (meters). |
GetVelocity() |
float |
Gets the current tendon velocity (m/s). |
GetLength¶
Gets the current tendon length (meters).
- Signature:
GetLength() - Blueprint: 🔵 Callable
- Returns: float
GetVelocity¶
Gets the current tendon velocity (m/s).
- Signature:
GetVelocity() - Blueprint: 🔵 Callable
- Returns: float