V2020.1.56.3_ Wheel Joint



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 > Add Kinematics > 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 Kinematics Controller in the hierarchy

The following inspector component 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 Kinematic Update on this GameObject

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 Leading Transform Relation

Creates a new leading relation between Transforms

Create new Trailing Transform Relation

Creates a new trailing relation between Transforms

Trailing Transforms are obsolete and will be removed in the near future

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

Motion Direction is Reversed

When enabled, the manipulation to/from the opposing kinematic transform is inverted

Wheel Joint Settings

 

Also Manage Translation

Locks the position of the Wheel Joint object

Wheel Radius

The Radius of the Wheel Joint

Use Sceen Gizmo to set Radius

When checked a handle in the Scene view is added and can be manipulated manually to set the Wheel Radius

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

The notation of the limits. 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

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

Wheel Joint State

 

Current Rotation Notation

The notation of the Current Rotation State. 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

Current Rotation State

Current rotation of the wheel joint

Relative Rotation Space Share

Describes the current rotation of the Wheel Joint relative to its total limited rotation range. Normalized between 0 and 1

Sceneview Settings

 

Show in Sceneview

When checked all gizmo’s and handles of the Wheel Joint are shown in the scene view

Show when not selected

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 color

The color of the Wheel Radius

Axis Direction color

The color for the Wheel Axis Direction

Forward Direction color

The color for the Wheel Forward Direction

Current Rotation color

The color for the Current Rotation State

Rotation Limit Color

The color for the Minimum Rotation Limit and Maximum rotation limit


How to use

1. Add a Wheel joint to an object

2. 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 required

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

1. 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