13.2 Applying Glazing Percentages to the Mass Model

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This exercise will help you understand how assigning glazing values works in Conceptual Mass models (using the sample model provided).

The Overall Glazing setting for the project (Window to Wall ratios) may be defined in the Performance Manager  by setting the Current Percentage Glazing value.  This will apply to all Facades and Surfaces in the project. It may be set initially and may also be later adjusted.

Choose a Conceptual Mass model for this exercise.  A sample mass model is available here.

Open a Mass model and launch FenestraPro.   If this model has not been opened before, you may need to calculate results in the Building Manager and then close this window. Have the Performance tab open and you may open the Charts to review the results.  There should be no glazing percentage set yet.  This may be done by typing in 0.00 in the Overall Percentage Glazing box and press Return on your keyboard.  Open the Charts and review.   The Dashboard dials will display zero for most indicators. The Charts will also have no results at this stage.

Note: For Revit 2023 and older, there is a display setting in Revit to help visualize the glazing on the model better.  You can find this on the Revit Menu under Massing & Site – Show Mass Surface Types.  This Revit setting may not be available in Revit 2024.

Sample Workflow:

1. Set the Window to Wall ratio in the Performance Manager

  • Ensure that all Facades are unlocked
  • Facades which are unlocked will have the Current Percentage Glazing value applied
  • For example, set 50% for Current Percentage Glazing in the Performance Manager
  • Press Return on the keyboard
  • In the Charts and Dashboard, view the glazing percentage for all Facades (50%)
Apply 50% Glazing Overall

2. Lock a selection of Surfaces

    • Lock Surfaces by making a selection in the Façade Navigator list and then uncheckingSelected surfaces unlocked’ (this will then displaySelected Surfaces locked
    • To do this, click on the vertical blue bar at the left hand side to open the Facade Navigator.  Once selections are made, switch to the Facades tab and you may lock these selections.  Click in the main window (outside the Facade Navigator) and click on the Facades tab to access this area
    • In this example, Facades 1 – 5 will now be locked so that these will remain at 50%
    • Click back into the Facade Navigator and expand the Facade lists.   A padlock symbol will appear bedside locked Surfaces/Facades in the list to indicate which are currently locked
    • The selections will highlight on the model also
Facades 1-5 only selected and locked

When you expand the list of Surfaces, padlock symbols will appear beside the locked Surfaces.

Locked Surfaces will display a padlock symbol

3. Select All Facades (some Facades/Surfaces are locked and will not be affected by the following changes even if they are selected)

  • Surfaces which are unlocked (Facades 6 – 8) are available for adjustment
  • These may be adjusted to 80% under the Façades tab
  • In the Glazing Specification Tab for Surfaces, type in 80 and press Return on the keyboard
  • The Charts will display updates to the new percentage (only for these unlocked selections)
The remaining Facades may be adjusted to 80%

The Overall Glazing value will have changed since the 50% overall could not be maintained

4. Deselect All  in the Facades List and view the Glazing Charts

  • This will allow you to view all Facades (when Select All is used, all Surfaces will display instead of Facades)
  • Surfaces which were locked remained at 50% (they were not modified when other Surfaces are adjusted)
  • Only Surfaces which were unlocked were changed to 80%
  • Alternatively, you could apply 80% for Overall Percentage Glazing in the Performance tab and this would only be applied to the unlocked Facades
Deselect All in the Facades List
Only unlocked Facades were updated to 80%

5. Review the Overall Percentage Glazing in the Performance tab

  • Click outside the Facade Navigator to allow it to collapse
  • In the Performance tab, review the Overall value.  It has now changed.  This is because enough Surfaces with sufficient area have been raised to 80% and this has affected the Overall value.

    Overall Glazed Percentage adjusts if enough Surfaces are modified

6. Auto-Distribute

  • Select Facades 1 – 4 and unlock them
  • Leave Facade 5 locked
Unlock any Facades which were previously locked
Leave Facade 5 locked at 50%
  • Deselect All in the Facades List and switch to the Solar Loads Chart 
  • Facades have different Solar Loads acting on them since they have different orientations (South, East, West, North)
  • Color highlighting on the model indicates this (use Select All to highlight on the model with colors)

  • Then under the Facades tab, use the Auto-Distribute button to equalize the Solar Loads to all unlocked Facades on the model
  • Glazing areas are adjusted (on all unlocked Surfaces) to allow equalization of the Solar Loads to each orientation of the model

  • As Facade 5 is locked, all Surfaces on this Facade remain unaffected and its settings remain (the principle also works if individual Surfaces are locked)
  • Review the Glazing Chart to confirm that glazing has been adjusted on different Facades to allow this
  • The locked Facade 5, remains with its setting at 50% and was not adjusted

Note: only unlocked Surfaces with some glazing percentage will be adjusted.  Locked Surfaces and any Façade with 0% glazing will not be affected.

When using Auto Distribute, Solar Loads are distributed equally to all unlocked Surfaces.  This is done by adjusting glazing areas on any unlocked Surfaces.

The glazing percentage applied to each Surface will depend on the area of the Surface as a ratio of the total surface area.


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