> For the complete documentation index, see [llms.txt](https://docs.ladybug.tools/hb-energy-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/hb-energy-primer/components/1_constructions/opaque_material_no_mass.md).

# Opaque Material No Mass

![](/files/-MihpfvcVUVUxJ2iH81r)

![](/files/-Ma9OY6Epp7nTKGLm6e5) - [\[source code\]](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.