# 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)
{% 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.
{% 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.
