> ## 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.

# Volume Fraction Response

Create a Design Response that measures the fraction of material usage in some region. The response is computed by integrating the relative density field over the region. Values can range from 0 to 1.

### Inputs

| Name   | Type                                                   | Description                                                                                                                      |
| ------ | ------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------- |
| Region | [Region](../../../../block-documentation/types/region) | Region that the design response will be computed in. If not provided, then the response will be calculated for the entire model. |

### Outputs

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