Watt Extension


Watt SketchUp extension calculates the solar spectrum irradiance (W/m²) on the external surfaces of a SketchUp model.

DL-Light extension Watt Sketchup model snapshot

Information about the energy received by model's surfaces can influence important decisions related to building lighting and thermal strategies:

Solar irradiance on a point of the facade depends on building site weather and environment (relief, obstruction buildings), selected time period and also building shape, facades orientation and sun protections. Surrounding materials, such as ground reflectance or materials of environement facades also influence energy falling on surfaces.

How To Use Watt Extension

  1. Open SketchUp model. Follow recommendations to prepare your model for DL-Light calculations.

  2. Open Watt dialog from toolbar wa_dialog_icon or menu option Extensions -> De Luminae -> Watt -> Activate extension and enter the parameters of the calculation.

    DL-Light extension Watt  General tab

    Fields description:

  3. Define materials characheristics for energy calculation. Defined materials have influence for calculations 'with interreflections'.

    Since calculation is done with verified Radiance tools it is necessary to 'attach' physically based material to each layer in SketchUp. Note that materials should be defined with their solar reflectance and transmittance.

    The tab for choice of materials:

    DL-Light extension Watt Materials tab

    Materials panel consists of two main parts:

    To attach a material, select in the table layer(s) and either double-click on required material in the tree or select the material in the tree and press Attach/Detach button.
    To detach from the layer(s), select it and click Attach/Detach button.
    To revert all layers to previous state press Revert button.

  4. Palette of false colours can be defined with precision. 3 options for palette are given, Automatic, Gradient and Custom:

    DL-Light extension Watt palette tab
  5. After all data are entered in Watt dialog, select surfaces and press Render or run_selected button.

    DL-Light extension Watt Sketchup selection

    Calculation time depends on number of selected surfaces, level of sensors details and model's complexity.

  6. When results are imported, selected surfaces will have appropriate false colors and Palette and Report dalogs will be opened.

    DL-Light extension Watt Sketchup result imported - automatic palette
  7. Results analysis.

  8. For further calculations on the same model:

    DL-Light uses a calculation cache algorithm. It automatically detects if a surface requires recalculation or if a previous result can be reused. By default, the cache keeps the information of the last 10 calculations (value configurable in the preferences).

    For example if a calculation has just been made for the "summer" season, then the season is changed to "winter" for a recalculation, and finally recalculated for "summer":

  9. Archiving results:

    DL-Light allows to archive all the results of a calculation: reports, textures and calculation steps (exported Radiance model, weather file, ...). This archive can be reloaded on the model, subject to using exactly the same model as during the calculation.

    See the page Archiving results for more informations about this feature.

    See the page Comparison of results for more information about the comparison of archives.

  10. Snapshots:

    Current SketchUp model view with imported results can be exported with palette snapshot_with_palette_icon or without palette snapshot_icon to png format. To explore created images user can open folder where they are saved open_snapshot_folder_icon.
    This option is not supported in trial version of the extension (see license information).

    DL-Light extension Watt Sketchup model snapshot image