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Using Layout Assistant in Daylighting Mode (with electric lighting enabled) can be an effective way to determine how many luminaires can be switched or dimmed in an environment to achieve a desired light level with both daylight and electric light contribution. Layout Assistant will consider the daylight contribution at the specific date and time set in the Daylight Parameters dialog and then compute the number of luminaires required to amend the daylight contribution to meet the desired light level. This will require the use of masking in Layout Assistant to prevent new luminaires from being added in the areas illuminated by daylight. Additional dimmed luminaires can be considered by masking them from the estimating process as well if necessary. Let's illustrate with an example.
The room shown has five windows facing East and a lighting layout that produces 50 fc average without daylight. At 9:00 AM shades are drawn to mitigate direct solar penetration so we will focus on the afternoon use case. What is possible in terms of switching luminaires at 3:00 PM if we still want to meet the same average illuminance?
The project is in Alamogordo, NM and we are looking at September 21st at 3:00 PM MDT. We are using the Perez sky with weather station data from Holloman Air Force Base as set in the Daylight Parameters dialog shown below.
Masking requires either geometry you can select (an Element), or a Region created in Revit that can be used for masking an area. These are items that must be in place before you use Layout Assistant. By masking an area, Layout Assistant will not consider any of the luminaires inside the masking region.
STEP 1 - Enable Electric lighting in the Daylight Parameters dialog.
STEP 2 - Start the Layout Assistant and select the room.
STEP 3 - Select the Luminaire button and click on one of the luminaires in the room.
STEP 4 - Select the Mask Regions button, click on the Revit region created previously. This will mask the area where we do NOT want to consider electric lights. This would be analogous to the lighting zones that are to be switched Off with the daylighting contribution.
STEP 5 - Click the Ceiling Grid tile button and set three points to define where the ceiling grid resides.
STEP 6 - Click the Layout Assistant button.
When the Layout Assistant opens you will see the masked area in dark gray.
STEP 7 - Enter the desired illuminance level (average) in the cell shown. Layout Assistant will produce three layouts, the highlighted icon reflects the layout currently shown.
STEP 8 - Examine the three layouts. You can pick the one that matches your existing positions, or you may have to adjust them using the Row and Column adjustments. Click the Calculate button.
We now know that the masked luminaires can be switched off at 3:00 PM on September 21 while maintaining adequate illumination from both daylight and electric light.
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