The Horizontal Sight Angle is the measurement at a point of the viewing angle towards the outside. The openings are the windows looking towards the exterior of the building. The horizontal sight angle of a room completely closed is 0°, the horizontal sight angle of a flat surface without any wall around is 360°.
The Horizontal Sight Angle indicator is used in particular by the European standard EN 17037 (in UK: BS EN 17037:2018 Daylight in buildings).
The EN 17037 standard uses 3 thresholds for the sight angle: 14°, 28° and 54°. This extension makes it possible to analyze a surface according to a customizable scale that can give more information during the design phase than these 3 thresholds.
According to standard EN 17037 the measurements can be carried out at a height of 1.2m or 1.7m from the floor. The distance of 1.2m is the default setting of the virtual surfaces for this extension (value configurable in the preferences). For the use of virtual surfaces, see page: Create virtual surfaces.
Important: layers corresponding to glazing must be hidden.
Open SketchUp model. Follow recommendations to prepare your model for DL-Light calculations.
Open Horizontal Sight Angle dialog from toolbar or menu Extensions -> De Luminae -> Horizontal Sight Angle -> Horizontal Sight Angle computation and enter the parameters of the calculation.
Project name - Project name is used during export and for output filenames generation. The SketchUp model name is used by default.
Results - Directory where
model will be exported for calculation. It should be an
existing or a new directory where user has appropriate
write/read privileges. When calculation is started model
geometry and resulting files will be saved in
For SketchUp projects stored on network disk (Windows), see Work on a copy of the model.
Details - By default, Horizontal Sight Angle calculation uses a dedicated grid 'HSA grid' with 25 sensors per square meter. This density allows to have a sufficient resolution to assess the sight angle in a room with standard openings such as Windows.
DL-Light allows to choose:
See sensors selection for more information on the choices of proposed sensors.
Transparency - The calculation requires that landscape and surrounding buildings are invisible or transparent.
Use the layer visibility feature of SketchUp, or the dedicated layer transparency interface of DL-Light. This interface allows you to define layers:
See page Make layers "transparent" for more details.
The default color palette is a non-linear scale:
To obtain a grid with only the EN 17037 thresholds, just create a custom palette by removing the intermediate thresholds: click on a level to remove, then on the "minus" button.
After entering the parameters, select surfaces and press Render or button.
Calculation time depends on number of selected surfaces and model complexity.
When results are imported, selected surface will have appropriate false colors and Palette and Report dialogs will be opened.
Report dialog - shows distribution of results over current palette and calculation input parameters.
The 'total' column displays the area of the surface with sky visibility. The display of this column is configurable in preferences.
For further calculations in the same model:
Since version 8.0, 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, restarting calculation with another palette is fast, here with the thresholds of standard EN 17037:
DL-Light allows to archive all the results of a calculation: reports, textures and calculation steps (exported Radiance model ...). 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 informations about comparison of several archives.
Current SketchUp model view with imported results can be exported
or without palette
to png format. Open the folder of images with .
This option is not supported in trial version of the extension (see licence information).