> For the complete documentation index, see [llms.txt](https://docs.m-xr.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.m-xr.com/marso-measure/getting-started/photogrammetry/mask-mesh-and-manual-uv-unwrap.md).

# Mask Mesh & Manual UV Unwrap

### Mask Mesh

The Mask Mesh is a separate mesh file from the Subject Mesh. It should contain any geometry within the scene that occludes the subject from a given camera view.

In this example, the plinth occludes the shoe for the lower cameras (see below)

<div><figure><img src="/files/Tx0JOnwytBma36ijvJFO" alt="" width="563"><figcaption></figcaption></figure> <figure><img src="/files/GROdymxtmemaxBj687fU" alt=""><figcaption></figcaption></figure></div>

{% hint style="warning" %}
If the plinth is not included within the scene, parts of the plinth will be mistakenly projected onto the underside of the shoe.
{% endhint %}

To avoid this, use a separate 'Mask Mesh' to denote unwanted geometry that occludes the subject, in this case, the plinth. **Blue (Asset)** will be used for the final texture, **Red (Plinth)** will not.

<div><figure><img src="/files/kUJauKrjVqVpUdxf0ZNy" alt="" width="563"><figcaption></figcaption></figure> <figure><img src="/files/CrqvV0XOynAUqrXuF7sF" alt="" width="563"><figcaption></figcaption></figure></div>

{% hint style="danger" %}
Make sure the Subject is not present in the mask mesh, otherwise no textures will be produced.

Providing a mask mesh ensures that these areas will not affect the final asset, as otherwise they can be projected across the surface, leading to problems in the final textures.
{% endhint %}

***

### Manual UV Unwrap

You are welcome to UV unwrap the mesh yourself in an application of your choosing before importing it into Marso Measure.

**Photogrammetry → .abc → UV Unwrap → .abc → Marso Measure**

Just be sure to **adhere** to the following:

* You **must** export this new mesh as an alembic (.abc) file, with cameras, normals, and triangles rather than quads.
* Only do a single UV Page.
* Ensure the scale or units of the Object & Scene **does not change** upon export.
* Ensure that the cameras are exported within the alembic (.abc) file and have not been renamed or re-ordered.


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