====== Wheel Rotation ======
{{ :tools:pasted:20210208-133136.png}}

This node computes the rotation of a wheel if travelling along a distance. The distance is based on the movement of an item.

===== Controls =====

==== Wheel Radius ====

Use this control to enter the radius of the wheel to rotate.
This value can currently not be enveloped because that would require evaluating the whole envelope up to the current frame every time the node is evaluated.

==== Movement Reference ====

The reference item to use to compute a travelled distance. This may be the wheel itself if "Use World Distance" is used.

==== Forward Direction ====

The direction (in local coordinates) on the Movement Reference that will be designated as forward in the direction of travel.

==== Use World Distance ====

Use the world coordinates of the Movement Reference item to compute the travelled distance. If disabled, the local movement of the item is used.

==== Use X/Y/Z Distance ====

Toggle which axis positions are used to compute the travelled distance.

==== Align ====

This aligns the wheel to the rotation of travel. The wheel may travel backwards as well. If that happens, the alignment will not flip (it also shouldn't either).

Travelling backwards is detected by the motion changing by more than 90° from one frame to the next.

<WRAP center round tip >
If Align is active, the plugin will assume a default orientation for the wheel.
The forward direction is -Z, it will rotate around the pitch and the alignment modifies the heading.
</WRAP>

==== Look-Ahead (s) ====

How far the plugin will look ahead to compute the alignment.
==== Samples per Frame ====

If the movement has intricate turns, increasing the number of samples will increase the accuracy of the computed distance - but will also slow down evaluating it.

==== First Frame / Override ====
==== Last Frame / Override ====
This controls allow you to limit the frames where the plugin is active.
Multiple plugins can be daisy chained via the Rotation input and using Add as a Channel Replacement option to allow for multiple slices in time where the plugins are active.
A similar effect can be achieved by animating the Rotation Multiplier.


==== Rotation Multiplier ====

These envelope is evaluated as the travelled distance for the wheel is computed. A value of less than 100% will slow down the wheel rotation (0% is a complete standstill), a value higher than 100% speed up the rotation.
This can be used to lock wheels or overcrank them.

==== Rotation Channel ====

This determines the rotation channel the wheel rotation will be copied to if the **Rotation Vector** output is used.

==== Channel Replacement ====

If a Rotation vector is connected to the input, this control defines how the **Rotation Channel** will modify the respective rotation channel on the input vector.
This allows for the daisy chaining of multiple wheel nodes.

==== Cache ====

If this option is enabled, the plugin will use a cache for the wheel rotation which can massively speed up scenes with multiple wheels or long scenes.

The Alignment is not cached.

==== Update Cache ====

Updates the cache. This is required if any of the items that influence the current wheel have been edited.

<WRAP center round important >
Due to technical limitations, the cache can not be updated automatically if any of the items that influence the current wheel have been changed.

We have provided the [[tools:wheel_generic|]] plugin to make this process easier.
</WRAP>

==== Save Cache ====

Saves the cache with the node settings, effectively baking it.

If save is off, the cache will be re-created when the node is loading (i.e. when a scene is loaded).



===== Node Connections =====

==== Rotation ====
The rotation of a wheel travelling the path of the Movement Reference item up to the current frame.
==== Distance ====
The total distance travelled by the Movement Reference item up to the current frame.

==== Rotation Distance ====
The distance travelled by the Movement Reference item up to the current frame taking the **Rotation Multiplier** into account.

==== Rotation (Input) / Rotation Vector (output) ====
The Rotation input is passed through to the Rotation output. Any computed wheel rotation will replace the rotation channel selected by the **Rotation Channel** Control



 


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This plugin is our Plugin of the Month for October 2020 and December 2020, made possible by the finest patrons on [[https://www.patreon.com/dbw|Patreon]].

**Sponsored by Mikael "Cageman" Burman.**