# Combine materials

> Use this feature along with scene.mergePartOccurrences to combine part occurrences and their assigned materials.

API function: [algo.combineMeshes](/asset-transformer-sdk/2026.4/api/python/algo_functions.md#combinematerials)

Use this feature along with [scene.mergePartOccurrences](/asset-transformer-sdk/2026.4/api/python/scene_functions.md#mergepartoccurrences) to combine part occurrences and their assigned materials.
The result is a similar looking model, but the number of draw calls is reduced.

![](/api/media?file=/asset-transformer-sdk/media/images/algo-combine-meshes.jpg)

These operations are performed:

* Geometries are merged, but they aren't modified.
* Texture coordinates are combined and repacked into a single atlas.
* Material information is transferred to a single set of textures. This set is used by a single material that's applied to the combined mesh.

You can regenerate texture coordinates.

This feature bakes these maps:

* Albedo
* Normals
* Opacity
* Roughness
* Specular
* Metallic
* Ambient occlusion

The output material contains the packed textures atlas:

![](/api/media?file=/asset-transformer-sdk/media/images/combine.png)