--- name: BodyVelocity last_updated: 2026-06-10T02:17:46Z inherits: - BodyMover - Instance - Object type: class memory_category: Instances tags: - Deprecated summary: "Applies a force to maintain a constant velocity." --- # Class: BodyVelocity > Applies a force to maintain a constant velocity. ## Description The `BodyVelocity` object applies a force on an assembly such that it will maintain a constant velocity. The [Velocity](/docs/reference/engine/classes/BodyVelocity.md) property, not to be confused with [BasePart.AssemblyLinearVelocity](/docs/reference/engine/classes/BasePart.md), controls the goal velocity. [BodyVelocity](/docs/reference/engine/classes/BodyVelocity.md) is the linear counterpart to [BodyAngularVelocity](/docs/reference/engine/classes/BodyAngularVelocity.md). If you need the assembly to move toward a goal position, use [BodyPosition](/docs/reference/engine/classes/BodyPosition.md) instead. If you need further control on a force applied to an object, consider using a [BodyForce](/docs/reference/engine/classes/BodyForce.md) or [BodyThrust](/docs/reference/engine/classes/BodyThrust.md) instead. The strength of the force applied by this object is controlled by several factors, namely the difference between the assembly's current velocity and the goal velocity. This is multiplied by [P](/docs/reference/engine/classes/BodyVelocity.md) (power) to either amplify or diminish it. The resulting force is then capped by [MaxForce](/docs/reference/engine/classes/BodyVelocity.md). ## Properties ### Property: BodyVelocity.MaxForce ```json { "type": "Vector3", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Goals", "capabilities": [ "Physics" ] } ``` This property determines the limit on the amount of force that may be applied on each axis in reaching the goal [Velocity](/docs/reference/engine/classes/BodyVelocity.md). If an assembly isn't moving, consider increasing this value and also check that it is not [Anchored](/docs/reference/engine/classes/BasePart.md) or attached to any anchored assemblies. ### Property: BodyVelocity.P ```json { "type": "float", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Goals", "capabilities": [ "Physics" ] } ``` This property determines how much power is used while applying force in order to reach the goal [Velocity](/docs/reference/engine/classes/BodyVelocity.md). The higher this value, the more power will be used and the faster it will be used. The force the [BodyVelocity](/docs/reference/engine/classes/BodyVelocity.md) exerts increases as the difference between the assembly's current velocity and the goal velocity increases. This property is multiplied to this force to either amplify or diminish it. ### Property: BodyVelocity.Velocity ```json { "type": "Vector3", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": true }, "thread_safety": "ReadSafe", "category": "Goals", "capabilities": [ "Physics" ] } ``` This property (not to be confused with [BasePart.Velocity](/docs/reference/engine/classes/BasePart.md)) determines the target velocity towards which force will be exerted. It is specified relative to the world, not the assembly. ### Property: BodyVelocity.maxForce ```json { "type": "Vector3", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": false }, "deprecated": true, "thread_safety": "ReadSafe", "category": "Goals", "capabilities": [ "Physics" ] } ``` > **Deprecated:** This property is a deprecated variant of [BodyVelocity.MaxForce](/docs/reference/engine/classes/BodyVelocity.md) which should be used instead. ### Property: BodyVelocity.velocity ```json { "type": "Vector3", "access": "ReadWrite", "security": { "read": "None", "write": "None" }, "serialization": { "can_load": true, "can_save": false }, "deprecated": true, "thread_safety": "ReadSafe", "category": "Goals", "capabilities": [ "Physics" ] } ``` > **Deprecated:** This property is a deprecated variant of [BodyVelocity.Velocity](/docs/reference/engine/classes/BodyVelocity.md) which should be used instead. ## Methods ### Method: BodyVelocity:GetLastForce **Signature:** `BodyVelocity:GetLastForce(): Vector3` This method is not implemented and it will always return the `0` vector. You are advised to use [AlignPosition](/docs/reference/engine/classes/AlignPosition.md) instead. *Security: None · Thread Safety: Unsafe · Capabilities: Physics* **Returns:** `Vector3` ### Method: BodyVelocity:lastForce **Signature:** `BodyVelocity:lastForce(): Vector3` Returns the last force in the object. *Security: None · Thread Safety: Unsafe · Capabilities: Physics* **Returns:** `Vector3` ## Inherited Members ### 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