> For the complete documentation index, see [llms.txt](https://docs.ladybug.tools/dragonfly-primer/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ladybug.tools/dragonfly-primer/components/6_alternativeweather/assign_model_uwg_properties.md).

# Assign Model UWG Properties

![](/files/-MihraCXjm1txDG9AwWh)

![](/files/-Ma9gLoT5SuIJJLKUJ-J) - [\[source code\]](https://github.com/ladybug-tools/dragonfly-grasshopper/blob/master/dragonfly_grasshopper/src//DF%20Assign%20Model%20UWG%20Properties.py)

Edit the properties of a Dragonfly Model that affect simulation with to the Urban Weather Generator (UWG).

## Inputs

* **model \[Required]**

  A Dragonfly Model which is to have its Urban Weather Generator (UWG) properties assigned. 
* **terrain**

  A Terrain object that dictates the properties of the street and ground beneath the buildings. If None, a default terrain object will be generated by analysing all of the buildings in the Model and drawing a bounding rectangle in the XY plane around them. 
* **traffic**

  A TrafficPararameter object that defines the activity and intensity of traffic within the urban street canyons. If None, traffic intensity will be approximated using the average building story count along with a generic traffic schedule. 
* **tree\_cover**

  A number from 0 to 1 that defines the fraction of the exposed terrain covered by trees. If None, it will be determined by evaluating the horizontal area of all ContextShade geometry that has a true is\_vegetation property. 
* **grass\_cover**

  A number from 0 to 1 that defines the fraction of the exposed terrain that is covered by grass or shrubs. If None, no grass will be assumed for the urban area. 

## Outputs

* **report**

  ... 
* **model**

  The input Dragonfly Model with its UWG properties re-assigned based on the input.