A specific variation of the Projected calculation points command allows calculation points to be projected to a topographical map resulting in computed values at diverse elevations. This is a new and powerful capability in lighting design software opening the door to complete 3-dimensional exterior lighting calculations.

The Topography version of Projected points will use Revit's Topography entities as a calculation boundary when projecting points downward, this includes Building Pads. Projected points can also be attached to multiple entity types that may be present such as ramps and masses.

Consider the simple example of two building pads as shown here. The lower pad is at an elevation of zero while the upper pad is at fifteen feet.

Using the Topography command we can add calculation points to both building pads and the terrain in one step by selecting all three entities. Or, we can add points to only the two building pads, or finally, we can add points to the terrain and then add the pads as additional Footprints from within the dialog. We'll use the third option as it allows us to illustrate the features available from within the dialog.

Calculation Point Dialog - Topography

Once the topography has been selected, the Add Calculation Points dialog will appear for you to assign specific details to the calculation points. Typical input will be Point spacing and possibly a Workplane height should the points need to be elevated above the surface(s). By default, the illuminance Metric is selected and all Modes are active (General Use, Emergency, Daylight and Horticulture) for the grid of points. You can make changes if necessary by opening these sections of the dialog.

Specific details with regard to point locations can be accessed from the Projection Options section of the dialog.

Footprint - The Footprint section lists the regions or elements used to create the boundary of the projection. You have the option to Select or Draw additional entities to be included in the footprint area using the buttons. This will return control to the drawing area to revise the selection.

Targets - The Targets sections lists the Revit entities found by the projection footprint. The Targets section has three tabs: Include, Exclude and Mask. By choosing the appropriate action tab you have the ability to Select entities to be used for that action from the button. Actions can also be controlled by Revit Category.

TIP: In order for Revit Masses to be considered in the Targets section the Masses category must be visible in the ElumTools Working View (3D view created by ElumTools).

In this example: click the Select button under Footprints to return to Revit and select the two building pads.

There are also light poles in this project. They are objects and can be intersected by projected points, especially if they are in the center of the pad (common). We can prevent this by using the masking tab to mask the Lighting Fixtures Category (below).