Spatial Daylight Autonomy (sDA / ASE) Extension


Spatial Daylight Autonomy (sDA) assesses whether a space receives sufficient daylight on a work plane during standard operating hours on an annual basis. The target is 300 lux for 50% of the occupied period.

This extension also calculates the associated indicator ASE (Annual Sunlight Exposure). ASE identifies surfaces receiving too much direct sunlight that may cause visual discomfort (glare) or additional cooling costs. ASE measures the percentage of the work plane exceeding the threshold of 1000 lux more than 250 occupied hours per year.

The sDA and ASE indicators are part of the LEED rating system. They are defined in the IES LM-83-12 standard:

Illuminating Engineering Society, Lighting Measurement 83: Approved Method: IES Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE)

This extension is designed to follow the recommendations of the standard:

DL-Light extension sDA daylight spatial DA Sketchup model

The extension offers two modes for sDA:

For detailed analyzes, in both modes, you can display either the performance ("preferred", "nominally accepted", "low"), or the zone reaching the threshold "sDA300,50%", or the duration above the illuminance threshold.

By default, the calculations of sDA and ASE are performed simultaneously in order to garanty their consistency. The report presents the two indicators for each surface.

How To Use spatial Daylight Autonomy (sDA / ASE) Extension

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

  2. Open sDA / ASE dialog from toolbar sDA dialog icon or menu option Extensions -> De Luminae -> sDA / ASE (spatial DA) -> Activate extension and enter the parameters of the calculation.

    DL-Light extension sDA daylight spatial DA general tab

    Fields description:

  3. Define materials characheristics.

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

    DL-Light extension sDA Materials tab

    Materials panel consists of two main parts:

    To attach a material, select in the table layer(s) and either double-click on the chosen 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. The palette of false colors uses the defined thresholds. It is possible to change the various colors. The palettes for the analyzes sDA, ASE, sDA area and sDA duration:

    DL-Light extension sDA palette performance
    DL-Light extension sDA palette ASE
    DL-Light extension sDA palette surface
    DL-Light extension sDA palette duration
  5. After all data are entered, select one or more surfaces and press Render or run_selected button.

    As glazings are used for this calculation, it may be practical to use the DL-Light select by layer dialog DL-Light select by layer to select the areas to be calculated.

    DL-Light extension sDA SketchUp selection

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

    The "Daylight Autonomy" type of calculation (often referred to as "3-phases" calculation) is the most time consuming. DL-Light uses a caching system to switch between sDA and ASE analyzes without triggering a full calculation.

    By default, the sDA calculation also performs the ASE calculation. It is possible to modify this option in the preferences. The sDA calculation is then slightly faster and the ASE calculation is only performed when its display is requested:

    DL-Light extension sDA SketchUp preferenes
  6. When results are imported, calculated surfaces will have appropriate false colors and Palette is opened.

    Rendering of the sDA analysis:

    DL-Light extension sDA result performance

    Rendering of the ASE analysis:

    DL-Light extension sDA result ASE

    Rendering for area and duration sDA analyzes:

    DL-Light extension sDA result surface duration
  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).

  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, providing it is exactly the same model as during the calculation.

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

  10. Comparison of results

    The comparison of two archives is displayed in a special report:

    DL-Light extension sDA comparison

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

  11. 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 sDA snapshot image