2020.1.1500.2 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 > Kinematics > Kinematic Joints > 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 Kinematic Controller in the hierarchy

The inspector for a newly added Prismatic Joint will look like this:

Feature layout

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

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 Kinematic Relation	The kinematic transform 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.
Reverse Motion Direction	When enabled, the manipulation to/from the opposing kinematic transform is inverted.
Limit Relation & Update Settings
Constraining Spline	Defines the spline to which the Prismatic Joint is bound to.
Prismatic Joint Settings
Spline Constraint Length	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 Control Point	Updates the Target Control Point to the current spline position.

How to use

Create a

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

Add the

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

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

Position the

Prismatic Joint object along the spline.

Select the point in

Target Control Point you wish to change and click Update Limit Control Point.