2020.1.60.3 Wheel Joint

1 Overview
2 Where to find
3 Feature layout
4 How to use
5 How to use limits

Overview

This kinematic relation is used to define a rotational constraint on an object.

Where to find

The Wheel Joint can be found under Mechanics > Kinematics > Kinematic Joints > Add Wheel Joint.

This will add the Wheel Joint component to the currently selected object or create a new empty GameObject with the component attached if no objects are selected.

Joints must be placed as children of a Kinematic Controller in the hierarchy.

The following inspector will be shown:

Feature layout

The image below shows the complete feature layout of the Wheel Joint component.

Generic Joint Settings
Pass Priority	Priority of the kinematic chain calculations. Higher numbers are calculated earlier.
Enforce Outside Playmode	Enforces the joint to work in edit mode.
Prevent Kinematic Update	Removes the joint from the kinematic chain calculations.
Prevent Further Updates on Object	Allows lower priority kinematic transforms on the same GameObject to be skipped in calculations.
Allow Direct User Input	Allows the user to manipulate the joint with the scene gizmo.
Min. User Input Translation Offset	The minimum value the user must input before translations are applied.
Min. User Input Rotation Offset	The minimum value the user must input before rotations are applied.
Kinematic Chaining
Create new Kinematic Relation	Creates a new relation between Transforms.
Opposing Relation Instance	The kinematic transform you want to link the joint to.
Relation Direction	Describes the direction of the manipulation of the Transforms. The following options are available: BIDIRECTIONAL: Allows for both kinematic transforms, when they are being manipulated, to manipulate each other equally. RECIEVE_ONLY: Allows for the joint, when it is being manipulated, to manipulate the opposing kinematic transform, but not the other way around. SEND_ONLY: Allows for the opposing kinematic transform, when it is being manipulated, to manipulate the joint, but not the other way around.
Relation Type	Used when 2 different size Wheel Joints need the same rotational speed. The following options are available: TRANSLATION: Translates the transforms using the Wheel Radius. ROTATION: Translates the transforms without using the Wheel Radius.
Reverse Motion Direction	When enabled, the manipulation to/from the opposing kinematic transform is inverted.
Wheel Joint Settings
Wheel Radius	The Radius of the Wheel Joint.
Use Sceen Gizmo for Radius	When checked a handle in the Scene view is added and can be manipulated manually to set the Wheel Radius.
Notation	The angle notation for the Wheel Joint inspector. The following options are available: DEGREES: displays the limits in degrees. REVOLUTIONS: Displays the limits in number of revolutions. RADIANS: Displays the limits in radians.
Limit Rotation	When checked, settings appear to set the minimum and maximum rotation of the Wheel Joint.
Minimum Rotation Limit	The minimum rotation limit of the Wheel Joint.
Use Scene Gizmo for Min. Rotation	When checked, a handle in the Scene view is added and can be manipulated manually to set the Minimum Rotation Limit.
Maximum Rotation Limit	The maximum rotation limit of the Wheel Joint.
Use Scene Gizmo to set Max. Limit.	When checked, a handle in the Scene view is added and can be manipulated manually to set the Maximum Rotation Limit.
Wheel Axis Direction	A Scene Vector describing the axis of the Wheel Joint.
Wheel Forward Direction	A Scene Vector describing the forward direction of the Wheel Joint.
Limit Rotation
Limit Rotation	When checked more settings appear to set the minimum and maximum rotation of the Wheel Joint.
Limit Notation
Minimum Rotation Limit	The minimum rotation limit of the Wheel Joint.
Use Scene Gizmo to set Min. Limit.	When checked a handle in the Scene view is added and can be manipulated manually to set the Minimum Rotation Limit.
Maximum Rotation Limit	The maximum rotation limit of the Wheel Joint.
Use Scene Gizmo to set Max. Limit.	When checked a handle in the Scene view is added and can be manipulated manually to set the Maximum Rotation Limit.
Current Rotation State	Current rotation of the wheel joint.
Sceneview Settings
Enable in Sceneview	When checked all gizmo’s and handles of the Wheel Joint are shown in the scene view if the GameObject is selected.
Always Enabled	When checked all gizmo’s and handles of the Wheel Joint are shown in the scene view even when the object is not selected.
Wheel Plane	The color of the Wheel Radius.
Axis Direction	The color for the Wheel Axis Direction.
Forward Direction	The color for the Wheel Forward Direction.
Current Rotation	The color for the Current Rotation State.
Rotation Limit	The color for the Minimum Rotation Limit and Maximum rotation limit.

How to use

Add a Wheel joint to an object.
Set the Wheel Axis Direction to the desired direction.

3. Set the Wheel Radius to the desired radius.

4. Create a new Transform Relation, add an Opposing Relation Instance and define the other settings as needed.

5. Test if the Transform Relations are working.

To test your Transform Relations outside of playmode make sure Enforce Outside Playmode is checked on both Joints.

How to use limits

Click the Limit Rotation checkbox.

2. Use the Minimum Rotation Limit and Maximum rotation limit fields or use the scene gizmo’s to set the limits.

3. Test if the limits work by manipulating both Joints.