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 # assign\_mesh\_regions

 Last update: 10.09.2025 

<a id="ansys.meshing.prime.VolumeMeshTool.assign_mesh_regions"></a>

#### VolumeMeshTool.assign\_mesh\_regions(target\_part\_id, target\_cell\_zonelets, source\_part\_ids, small\_regions\_volume\_fraction)

Assigns a region id to the cells in target cell zonelets of target part id. The region id is based on their location within source part ids.

- **Parameters:**
    
    **target\_part\_id**: Id of the target part.
    
    **target\_cell\_zonelets**: Ids of cell zonelets to be split into regions.
    
    **source\_part\_ids**: Ids of solids used as a reference for assigning regions.
    
    **small\_regions\_volume\_fraction**: Regions with volumes smaller than a specified fraction of the total volume are merged into their largest adjacent region. This helps to eliminate isolated cells and thin regions from the output.
- **Returns:**
    
    [`VolumeMeshToolResults`](ansys.meshing.prime.VolumeMeshToolResults.md#ansys.meshing.prime.VolumeMeshToolResults): Returns the VolumeMeshToolResults.
- **Return type:**
    
    [`VolumeMeshToolResults`](ansys.meshing.prime.VolumeMeshToolResults.md#ansys.meshing.prime.VolumeMeshToolResults)

### Notes

**This is a beta API**. **The behavior and implementation may change in future**.

### Examples

```pycon
&gt;&gt;&gt; results = volume_mesh_tool.AssignMeshRegions(target_part_id, target_cell_zonelets, source_part_ids, small_regions_volume_fraction)

```