V2020.1.56.3_ Helical Joint



Overview

Constrains the motion of a GameObject to translate / rotate over a Spline.


Where to find

The Helical Joint can be found under Mechanics > Add Kinematics > Helical Joint.

This will add the Helical 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 Helical 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 to which 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

Helical Joint Settings

 

Pitch

The distance from the crest of one thread to the next

Invert

When checked inverts the direction of the rotation

Limit Relation & Update Settings

 

Spline

The Spline along which the position and rotation of the Helical Joint is constrained


How to use

  1. Create a Spline and use it to define the path you want the Helical Joint to follow

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

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