> For the complete documentation index, see [llms.txt](https://dorreal-art.gitbook.io/dorreal_art_docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dorreal-art.gitbook.io/dorreal_art_docs/documentation/advanced/rotation-meshes-and-fixtures.md).

# Rotation Meshes & Fixtures

Echoluma uses a **fixture based rotation system** to control how lights aim and move.\
This allows you to simulate real world lighting rigs such as moving heads and tracking spotlights.

### How the System Works

Each light is controlled through a rotation hierarchy:

<div align="left" data-with-frame="true"><figure><img src="/files/Szd6Ky5AaJugZottz2Pn" alt=""><figcaption></figcaption></figure></div>

* **Pan Pivot** → horizontal rotation component (left / right)
* **Tilt Pivot** → vertical aiming component (up / down)
* **Roll Pivot** → axial rotation component (twist)
* **Forward Correction** → light's emitting direction

Each axis is handled by a separate pivot, creating clean and predictable motion.

### Rotation Behavior

* Rotation is applied in **local (blueprint) space**
* It does **not use world axes directly**
* The **light’s rotation defines the system orientation**

This means rotating the **fixture** determines how it behave.

<div align="left" data-with-frame="true"><figure><img src="/files/HdXwy8zak44ykIuggCAB" alt=""><figcaption></figcaption></figure></div>

### Using Fixtures (Meshes)

Fixtures can use custom meshes, or be left empty.\
In both cases, the rotation system continues to function.

#### When to Use Meshes

Use custom meshes if you want:

* Realistic fixture visuals
* Accurate representation of stage lights

#### When to Leave Empty

Leave them empty if you only need:

* Functional lighting behavior
* Performance focused setups

### Setting Up a Custom Fixture

{% stepper %}
{% step %}

### Import Your Mesh

Import your fixture mesh into Unreal.
{% endstep %}

{% step %}

### Check Orientation

Before assigning the mesh:

* Ensure the **forward direction** is correct
* Ensure the mesh is not rotated incorrectly on import

If this is wrong, rotation will feel broken.

<div align="left" data-with-frame="true"><figure><img src="/files/Z4nFYKn0bP1ihgaRZky9" alt=""><figcaption></figcaption></figure></div>
{% endstep %}

{% step %}

### Assign the Mesh

Set your meshes to correct pivots.&#x20;

If you have only one mesh, attach your mesh under the **Roll Pivot**.

This ensures it inherits:

* Pan
* Tilt
* Roll

in the correct order.
{% endstep %}

{% step %}

### Adjust Forward Direction

Use the **Forward Correction Component** if needed.

This helps fine-tune orientation, but:

{% hint style="warning" %}
It should not be used to fix completely incorrect imports.
{% endhint %}

<div align="left" data-with-frame="true"><figure><img src="/files/OQTqdiAtwchyb9weZ9s9" alt=""><figcaption></figcaption></figure></div>
{% endstep %}
{% endstepper %}

### Best Practices

* Align your mesh correctly before importing
* Use Forward Correction for small adjustments only
* Keep pivot hierarchy intact
* Test with simple movement before complex setups

<div align="left" data-with-frame="true"><figure><img src="/files/0XHnDWchhR25QjrGOaeN" alt=""><figcaption></figcaption></figure></div>

### Quick Test Setup

1. Add a light with fixture setup
2. Assign a simple movement or focus target
3. Press Play

Expected result:

* Light rotates smoothly
* Aiming feels natural
* No axis flipping or unexpected motion


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