# UV drop-down menu

The UV drop-down menu allows you to switch between [UV1](#uv1) and [UV2](#uv2) modes (ProBuilder does not use UV3 and UV4). __UV1__ provides texture mapping functionality, and __UV2__ provides options for lightmap UV generation.

<a name="uv1"></a>

## UV1

When you select **UV1** from the  UV drop-down menu, the **Actions** panel displays the default UV mapping.

![Default UV mapping for the UV1 mode](images/UVPanel_ActionPanel_NoSelection.png)

If you select the object before you open the UV Editor window, the Actions panel is empty. To enable editing the UVs, choose one of these element Edit modes:

- Click the [Face Edit Mode button](edit-mode-toolbar.md) and select one or more faces in the UV viewer to edit in either [Auto](auto-uvs-actions.md) or [Manual](manual-uvs-actions.md) UV mode.  
- Click the [Edge Edit Mode button](edit-mode-toolbar.md) and select one or more edges in the UV viewer to begin editing in [Manual](manual-uvs-actions.md) UV mode.
- Click the [Vertex Edit Mode button](edit-mode-toolbar.md) and select one or more vertices in the UV viewer to begin editing in [Manual](manual-uvs-actions.md) UV mode.

To switch between the [Auto](auto-uvs-actions.md) and [Manual](manual-uvs-actions.md) UV modes, click the **Convert to Manual** or **Convert to Auto** button at the top of the **Actions** panel. Both modes provide their own options in the Actions panel.

> **Note:** When using [Auto UVs](auto-uvs-actions) you may only edit UVs by face. Editing an edge or vertex automatically converts the selected UVs to [Manual UVs](manual-uvs-actions.md).



<a name="uv2"></a>

## UV2 (read-only)

When you select **UV2 (read-only)** from the UV drop-down menu, the **Actions** panel displays the [Lightmap UV Settings](https://docs.unity3d.com/Manual/LightingGiUvs-GeneratingLightmappingUVs.html) and the **Rebuild Selected UV2** button.

![Lightmap UV parameters](images/UVGenerationParams.png)

Set up the options for lightmap UV generation for the selected UV2s, then click the **Rebuild Selected UV2** button when you are finished.

> **Note:** This only affects the UV2s that are currently selected. If you want to rebuild the UV2s for the entire scene, use the [Lightmap UV Editor](Object_LightmapUVs.md) window instead.

## UV3 (read-only)

ProBuilder does not currently use this UV mode.

## UV4 (read-only)

ProBuilder does not currently use this UV mode.