> For the complete documentation index, see [llms.txt](https://docs.ladybug.tools/butterfly-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/butterfly-primer/components/00_create/create_case_from_tunnel.md).

# Create\_Case\_from\_Tunnel

![](/files/-LPHXTVRVHuLtC4V5n95)

Create Case from wind tunnel. -

## Inputs

* **name \[Required]**

  Project name.
* **BFGeometries \[Required]**

  List of butterfly geometries that will be inside the tunnel.
* **refRegions \[Optional]**

  Script variable createCaseFromTunnel
* **windVector \[Required]**

  A vector that indicates speed and direction of wind. Length

  of the vector will be used as windspeed and the unfied vector will be

  used for wind direction. For wind tunnel vector will be projected to

  XY plane.
* **refWindHeight \[Default]**

  Reference height for wind velocity (default: 10m).
* **landscape \[Default]**

  An integer between 0-7 to calculate z0 (roughness).

  You can find full description of the landscape in Table I at this

  link (onlinelibrary.wiley.com/doi/10.1002/met.273/pdf)

  0 > '0.0002'  # sea. Open sea or lake (irrespective of wave size),

  tidal flat, snow-covered flat plain, featureless desert, tarmac and

  concrete, with a free fetch of several kilometres

  1 > '0.005'   # smooth. Featureless land surface without any noticeable

  obstacles and with negligible vegetation; e.g. beaches, pack ice without

  large ridges, marsh and snow-covered or fallow open country.

  2 > '0.03'    # open. Level country with low vegetation (e.g. grass)

  and isolated obstacles with separations of at least 50 obstacle heights;

  e.g. grazing land without wind breaks, heather, moor and tundra,

  runway area of airports. Ice with ridges across-wind.

  3 > '0.10'    # roughly open. Cultivated or natural area with low crops

  or plant covers, or moderately open country with occasional obstacles

  (e.g. low hedges, isolated low buildings or trees) at relative horizontal

  distances of at least 20 obstacle heights

  4 > '0.25'    # rough. Cultivated or natural area with high crops or

  crops of varying height, and scattered obstacles at relative distances

  of 12-15 obstacle heights for porous objects (e.g. shelterbelts) or

  8-12 obstacle heights for low solid objects (e.g. buildings).

  5 > '0.5'     # very rough. Intensively cultivated landscape with many

  rather large obstacle groups (large farms, clumps of forest) separated

  by open spaces of about eight obstacle heights. Low densely planted

  major vegetation like bush land, orchards, young forest. Also, area

  moderately covered by low buildings with interspaces of three to

  seven building heights and no high trees.

  6 > '1.0'     # Skimming. Landscape regularly covered with similar-size

  large obstacles, with open spaces of the same order of magnitude as

  obstacle heights; e.g. mature regular forests, densely built-up area

  without much building height variation.

  7 > '2.0'     # chaotic. City centres with mixture of low-rise and

  high-rise buildings, or large forests of irregular height with many

  clearings.
* **make2dParams \[Optional]**

  Butterfly parameters to make a 2d wind tunnel.
* **meshParams \[Default]**

  Butterfly meshing parameters. You can set-up meshing parameters

  also on the blockMesh and snappyHexMesh components to overwrite this

  settings. Use this input to set up the meshing parameters if you are

  not running the meshing locally.
* **tunnelParams \[Default]**

  Butterfly tunnel parameters.
* **run \[Required]**

  Create wind tunnel case from inputs.

## Outputs

* **readMe!**

  Reports, errors, warnings, etc.
* **pts**

  Wind tunnel corners for visualization.
* **case**

  Butterfly case.

[Check Hydra Example Files for Create Case from Tunnel](https://hydrashare.github.io/hydra/index.html?keywords=Butterfly_Create%20Case%20from%20Tunnel)


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