> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Mass Response

Create a Design Response that measures the total mass in some region. The response is computed by integrating the density field over the region.

### Inputs

| Name   | Type                                                   | Description                                                                                                                                         |
| ------ | ------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| Region | [Region](../../../../block-documentation/types/region) | Region that the Design Response will be integrated over. If a region is not provided, the response will be integrated over the entire design space. |

### Outputs

| Type                                                                     |
| ------------------------------------------------------------------------ |
| [Design Response](../../../../block-documentation/types/design-response) |