---
name: PrismaticConstraint
last_updated: 2026-06-10T23:09:12Z
inherits:
  - SlidingBallConstraint
  - Constraint
  - Instance
  - Object
type: class
memory_category: BaseParts
summary: "Constraint which creates a rigid joint between two Attachments, allowing them to slide along one axis but not rotate."
---

# Class: PrismaticConstraint

> Constraint which creates a rigid joint between two
> [Attachments](/docs/reference/engine/classes/Attachment.md), allowing them to slide along one axis but not
> rotate.

## Description

A **PrismaticConstraint** creates a rigid joint between two
[Attachments](/docs/reference/engine/classes/Attachment.md), allowing them to slide along one axis but not
rotate. This constrains the attachments so that their **X** axes are collinear
but pointing in opposite directions. It also constrains the attachments so
that their **Y** axes are parallel.

This constraint inherits many properties from [SlidingBallConstraint](/docs/reference/engine/classes/SlidingBallConstraint.md)
including [ActuatorType](/docs/reference/engine/classes/SlidingBallConstraint.md),
[LimitsEnabled](/docs/reference/engine/classes/SlidingBallConstraint.md),
[Velocity](/docs/reference/engine/classes/SlidingBallConstraint.md), and more. Please refer to
[SlidingBallConstraint](/docs/reference/engine/classes/SlidingBallConstraint.md) for details on configuring a
[PrismaticConstraint](/docs/reference/engine/classes/PrismaticConstraint.md).

When configuring this constraint, it may be helpful to study
[Roblox Units](/docs/en-us/physics/units.md) to understand how Roblox units
compare to metric units.

## Inherited Members

### From [SlidingBallConstraint](/docs/reference/engine/classes/SlidingBallConstraint.md)

- **Property `ActuatorType`** (`ActuatorType`): Sets whether the translation of the SlidingBallConstraint is
- **Property `CurrentPosition`** (`float`): The current offset between the constraint's
- **Property `LimitsEnabled`** (`boolean`): Sets whether the SlidingBallConstraint will limit the range of
- **Property `LinearResponsiveness`** (`float`): Specifies the "sharpness" of the linear servo motor in reaching the
- **Property `LowerLimit`** (`float`): The lower positional limit along the **X** axis of
- **Property `MotorMaxAcceleration`** (`float`): The constraint's maximum acceleration when
- **Property `MotorMaxForce`** (`float`): The constraint's maximum force when
- **Property `Restitution`** (`float`): The elasticity of the constraint's Attachments when
- **Property `ServoMaxForce`** (`float`): The constraint's maximum force when
- **Property `Size`** (`float`): The constraint's visualized size.
- **Property `SoftlockServoUponReachingTarget`** (`boolean`):  *(deprecated)*
- **Property `Speed`** (`float`): The constraint's desired speed when
- **Property `TargetPosition`** (`float`): The constraint's attempted target position when
- **Property `UpperLimit`** (`float`): The upper positional limit along the **X** axis of
- **Property `Velocity`** (`float`): The constraint's attempted velocity when

### From [Constraint](/docs/reference/engine/classes/Constraint.md)

- **Property `Active`** (`boolean`): Indicates if the constraint is currently active in the world.
- **Property `Attachment0`** (`Attachment`): The Attachment that is connected to
- **Property `Attachment1`** (`Attachment`): The Attachment that is connected to
- **Property `Color`** (`BrickColor`): The color of the constraint.
- **Property `Enabled`** (`boolean`): Toggles whether or not the constraint is enabled.
- **Property `Visible`** (`boolean`): Toggles the constraint's visibility.
- **Method `GetDebugAppliedForce(bodyId: int): Vector3`**:  *(deprecated)*
- **Method `GetDebugAppliedTorque(bodyId: int): Vector3`**:  *(deprecated)*

### From [Instance](/docs/reference/engine/classes/Instance.md)

- **Property `Archivable`** (`boolean`): Determines if an Instance and its descendants can be cloned using
- **Property `archivable`** (`boolean`):  *(deprecated, hidden)*
- **Property `Capabilities`** (`SecurityCapabilities`): The set of capabilities allowed to be used for scripts inside this
- **Property `Name`** (`string`): A non-unique identifier of the Instance.
- **Property `Parent`** (`Instance`): Determines the hierarchical parent of the Instance.
- **Property `PredictionMode`** (`PredictionMode`): 
- **Property `RobloxLocked`** (`boolean`): A deprecated property that used to protect CoreGui objects. *(hidden)*
- **Property `Sandboxed`** (`boolean`): When enabled, the instance can only access abilities in its `Capabilities`
- **Property `UniqueId`** (`UniqueId`): A unique identifier for the instance.
- **Method `AddTag(tag: string): ()`**: Applies a tag to the instance.
- **Method `children(): Instances`**: Returns an array of the object's children. *(deprecated)*
- **Method `ClearAllChildren(): ()`**: This method destroys all of an instance's children.
- **Method `Clone(): Instance`**: Create a copy of an instance and all its descendants, ignoring instances
- **Method `clone(): Instance`**:  *(deprecated)*
- **Method `Destroy(): ()`**: Sets the Instance.Parent property to `nil`, locks the
- **Method `destroy(): ()`**:  *(deprecated)*
- **Method `FindFirstAncestor(name: string): Instance?`**: Returns the first ancestor of the Instance whose
- **Method `FindFirstAncestorOfClass(className: string): Instance?`**: Returns the first ancestor of the Instance whose
- **Method `FindFirstAncestorWhichIsA(className: string): Instance?`**: Returns the first ancestor of the Instance for whom
- **Method `FindFirstChild(name: string, recursive?: boolean): Instance?`**: Returns the first child of the Instance found with the given name.
- **Method `findFirstChild(name: string, recursive?: boolean): Instance`**:  *(deprecated)*
- **Method `FindFirstChildOfClass(className: string): Instance?`**: Returns the first child of the Instance whose
- **Method `FindFirstChildWhichIsA(className: string, recursive?: boolean): Instance?`**: Returns the first child of the Instance for whom
- **Method `FindFirstDescendant(name: string): Instance?`**: Returns the first descendant found with the given Instance.Name.
- **Method `GetActor(): Actor?`**: Returns the Actor associated with the Instance, if any.
- **Method `GetAttribute(attribute: string): Variant`**: Returns the value which has been assigned to the given attribute name.
- **Method `GetAttributeChangedSignal(attribute: string): RBXScriptSignal`**: Returns an event that fires when the given attribute changes.
- **Method `GetAttributes(): Dictionary`**: Returns a dictionary of the instance's attributes.
- **Method `GetChildren(): Instances`**: Returns an array containing all of the instance's children.
- **Method `getChildren(): Instances`**:  *(deprecated)*
- **Method `GetDebugId(scopeLength?: int): string`**: Returns a coded string of the debug ID used internally by Roblox.
- **Method `GetDescendants(): Instances`**: Returns an array containing all of the descendants of the instance.
- **Method `GetFullName(): string`**: Returns a string describing the instance's ancestry.
- **Method `GetStyled(name: string, selector: string?): Variant`**: Returns the styled or explicitly modified value of the specified property,
- **Method `GetStyledPropertyChangedSignal(property: string): RBXScriptSignal`**: 
- **Method `GetTags(): Array`**: Gets an array of all tags applied to the instance.
- **Method `HasTag(tag: string): boolean`**: Check whether the instance has a given tag.
- **Method `IsAncestorOf(descendant: Instance): boolean`**: Returns true if an Instance is an ancestor of the given
- **Method `IsDescendantOf(ancestor: Instance): boolean`**: Returns `true` if an Instance is a descendant of the given
- **Method `isDescendantOf(ancestor: Instance): boolean`**:  *(deprecated)*
- **Method `IsPropertyModified(property: string): boolean`**: Returns `true` if the value stored in the specified property is not equal
- **Method `QueryDescendants(selector: string): Instances`**: 
- **Method `Remove(): ()`**: Sets the object's `Parent` to `nil`, and does the same for all its *(deprecated)*
- **Method `remove(): ()`**:  *(deprecated)*
- **Method `RemoveTag(tag: string): ()`**: Removes a tag from the instance.
- **Method `ResetPropertyToDefault(property: string): ()`**: Resets a property to its default value.
- **Method `SetAttribute(attribute: string, value: Variant): ()`**: Sets the attribute with the given name to the given value.
- **Method `WaitForChild(childName: string, timeOut: double): Instance`**: Returns the child of the Instance with the given name. If the
- **Event `AncestryChanged`**: Fires when the Instance.Parent property of this object or one of
- **Event `AttributeChanged`**: Fires whenever an attribute is changed on the Instance.
- **Event `ChildAdded`**: Fires after an object is parented to this Instance.
- **Event `childAdded`**:  *(deprecated)*
- **Event `ChildRemoved`**: Fires after a child is removed from this Instance.
- **Event `DescendantAdded`**: Fires after a descendant is added to the Instance.
- **Event `DescendantRemoving`**: Fires immediately before a descendant of the Instance is removed.
- **Event `Destroying`**: Fires immediately before (or is deferred until after) the instance is
- **Event `StyledPropertiesChanged`**: Fires whenever any style property is changed on the instance, including

### From [Object](/docs/reference/engine/classes/Object.md)

- **Property `ClassName`** (`string`): A read-only string representing the class this Object belongs to.
- **Property `className`** (`string`):  *(deprecated)*
- **Method `GetPropertyChangedSignal(property: string): RBXScriptSignal`**: Get an event that fires when a given property of the object changes.
- **Method `IsA(className: string): boolean`**: Returns true if an object's class matches or inherits from a given class.
- **Method `isA(className: string): boolean`**:  *(deprecated)*
- **Event `Changed`**: Fires immediately after a property of the object changes, with some