# Opaque Material No Mass

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![](https://459479801-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-Ma9N5K8lMbAhbyBVgms%2Fuploads%2Fgit-blob-ab54a28fef11a2187c658a8fc7824610d3f52a73%2FOpaque_Material_No_Mass.png?alt=media) - [\[source code\]](https://github.com/ladybug-tools/honeybee-grasshopper-energy/blob/master/honeybee_grasshopper_energy/src/HB%20Opaque%20Material%20No%20Mass.py)

Create an opaque material that has no mass, which can be plugged into the "HB Opaque Construction" component.

## Inputs

* **name**

  Text to set the name for the material and to be incorporated into a unique material identifier. 
* **r\_value \[Required]**

  Number for the R-value of the material \[m2-K/W]. 
* **roughness**

  Text describing the relative roughness of a particular material. Must be one of the following: 'VeryRough', 'Rough', 'MediumRough', 'MediumSmooth', 'Smooth', 'VerySmooth'. (Default: 'MediumRough'). 
* **therm\_absp**

  A number between 0 and 1 for the fraction of incident long wavelength radiation that is absorbed by the material. (Default: 0.9). 
* **sol\_absp**

  A number between 0 and 1 for the fraction of incident solar radiation absorbed by the material. (Default: 0.7). 
* **vis\_absp**

  A number between 0 and 1 for the fraction of incident visible wavelength radiation absorbed by the material. Default value is the same as the *sol\_absp*. 

## Outputs

* **mat**

  A no-mass opaque material that can be assigned to a Honeybee Opaque construction.