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Prepare an ElumTools Model

Make sure the LAI Weather Database is installed.

The LAI Weather Database is NOT installed by default when installing the ElumTools Add-In. It is a separate download and installation process. If you have already been performing daylight calculations in ElumTools using the Perez Sky, you will have installed it previously. Here are the instructions for downloading and installing the weather database when using ElumTools.

Easiest: Set ElumTools in Daylight mode from the toolbar. Click on the Daylight Parameters button, which opens the Daylighting dialog. Click on the Sites button. A pop-up message will ask if you would like to download the Weather Stations Database. Select Yes, and then follow the prompts to complete the download and installation. It will take about 5-10 minutes altogether, depending on your computer speed and Internet connection. The download file is approximately 156 MB. After installation, it will be expanded to approximately 1 GB.

Alternative: You may also download the LAI Weather Database from our website. Follow all the prompts to download and install the database in the location that the installer suggests; that is where ElumTools will look for it.

More about the LAI Weather database

Settings in the ElumTools Daylight Parameters dialog

The following settings are all accessed from the ElumTools toolbar Daylight Parameters button.

Enable the Annual Simulation

With the Daylight Parameters command selected from the ElumTools toolbar, click the Enable Annual Simulation button at the top of the dialog. This sets ElumTools into the annual simulation mode so that any daylighting calculations that are executed in ElumTools will open Licaso to process the annual simulation. Single scene calculations are not possible when this switch is enabled.

Set the site location and orientation

The Revit project site specification is loaded into the daylighting dialog by default. You can click the Sites button to locate your project on a different site. Likewise, you can always return to the Revit project site using the Revit Project Site button. You can also simply enter the Latitude and Longitude in the cells provided.

Set the site orientation by entering the True North orientation of the model in degrees according to the CCE (Counter clockwise East) system (0 is East, 90 is North, etc.).

Select the Perez All-Weather Sky

Select the Perez All-Weather Sky and find the closest weather station to your site location using the Find Closest button.


General ElumTools Functions

The following steps take place elsewhere in ElumTools or Revit.

Place Calculation Points

Calculation points are required for an annual daylight simulation as Licaso must be able to compute the illuminance at each point for each hour of daylight. Place calculation points on the appropriate work planes or surfaces at the necessary spacing. IES LM-83-14 specifies a point spacing of 2' on center on a 2.5' workplane. TIP: Do not use a larger spacing as this affects the location of the daylight meters and subsequent accuracy of the calculations.

Use ElumTools Add Calc Points command to add points to Rooms, Spaces, Regions or Areas.


Ensuring your Transition Surfaces Work

Generally, windows, curtain walls and families with an exterior side will be facing in the correct direction by default. You can see the orientation of the exterior side in Revit by the location of the "flip" surface marker.

Additionally, you can make sure the windows and skylights face the correct direction by running a single scene daylight calculation and examining the rendered view in ElumTools. Enable the Daylight Transition Surface Direction indicators from within ElumTools Calculation Viewer (lower right corner in Display Options). The vectors should face inward.

Selecting the Calculation Method in ElumTools

If your project contains exterior geometry such as shading devices or other buildings that may contribute to the daylight performance, you must use ElumTools command Create Daylight Views to separate that geometry into interior and exterior surfaces. This command will automatically create an interior and exterior view for you to use (or you can use your own). Use Revit's Visibility Graphics command to switch off and on items in these views. See the ElumTools Help for more information.

You will then use the ElumTools Calculate Multiple Views command to execute the computation. Otherwise, you can use any of the ElumTools calculate commands to begin execution. The Calculate by View method can be handy even when exterior geometry is not in play as you can easily switch off extraneous objects and details that are not important to the overall calculation such as furniture.


More information on model preparation and daylighting can be found in the ElumTools Help.