# Merge Part Occurrences by Materials

> Use this feature to create one mesh per material from multiple meshes with various assigned materials.

API function: [scene.mergePartOccurrencesByMaterials](/asset-transformer-sdk/2026.4/api/python/scene_functions.md#mergepartoccurrencesbymaterials)

These options are available:

* Whether to merge parts that have no active material
* How to process parts whose **Visible** property is set to **False**:
  * Delete these parts
  * Set the **Visible** property of these parts to **True**
  * Merge these parts separately