V2020.1.56.3_ Prismatic Joint

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

Overview

Constraints the motion of a GameObject to a translation over a Spline.

Where to find

The Prismatic Joint can be found under Mechanics > Add Kinematics > Prismatic Joint and will be added to the selected object. Without a selection a Prismatic Joint will be added to a new Empty GameObject.

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

The inspector component looks as below:

Feature layout

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

Generic Joint Settings
Pass Priority	Priority of the kinematic chain calculations. Higher numbers are calculated earlier
Enforce Outside Playmode	Enforces the prismatic joint in edit mode
Prevent Kinematic Update	Removes the prismatic 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 prismatic 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
Opposing Relation Instance	The kinematic transform to which you want to link the prismatic 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 prismatic 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 prismatic joint, but not the other way around
Relation Type	Not yet implemented
Motion Direction is Reversed	When enabled, the manipulation to/from the opposing kinematic transform is inverted
Limit Relation & Update Settings
Spline Input field	Defines the spline to which the Prismatic Joint is bound to
Prismatic Joint Settings
Spline Constraint Lenght	The length of the spline
Current Spline Position	Normalized position of the Prismatic joint over the spline between 0 and 1
Target Control Point	The Spline point to be used for Update Limit ControlPoint
Update Limit ControlPoint	Updates the Target Control Point to the current spline position

How to use

1. Create a Spline and use it to define the path you want the prismatic joint to follow

2. Add the Spline to the Prismatic Joint and create a new Transform Relation, add an Opposing Relation Instance and define the other settings as required

3. 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. Position the Prismatic Joint object along the spline

2. Select the point in Target Control Point you wish to change and click Update Limit Control Point