Add Calculation Points

ElumTools can place discrete calculation point locations on any surface, work plane, topography or boundary line in your Revit model. ElumTools locates points specifically by the associated boundary type (Room, Space, Region, etc.) by selecting the appropriate variation from the command menu, or, to any boundary type by simply clicking the main command button. The selection of Multiple boundary types (Room, Space and Region for example) can be done by selecting the Multiple option. You can also select a boundary in Revit and then select the main Add Calculation Points command to achieve the same result.


Projected point commands require the creation of a footprint for the projection. See Add Calculation Points - Projected.

Basic Interior Use: Add Points - Room or Space Workplane

The most common interior application is the calculation of illuminance points at some work plane height. For commercial applications this is typically 2.5 feet (0.76 meters) above the floor. ElumTools makes this operation very simple for Revit Rooms or Spaces; simply select the command (Main button or Room or Space) and select the Room or Space of interest. You can also select multiple Rooms or Spaces using the Multiple command button, or by first selecting them in Revit (use Filter and window around an entire level if you like).


Once selected, the Calculation Points dialog will open to allow the specifics of the calculation point grid(s) to be defined. Illuminance is the default lighting metric when placing points in all operation modes with the exception of Horticulture, so typically the only inputs required are point spacing and workplane height. A Boundary Offset can be useful to move points away from walls and structure (shown) and unwanted points can be masked (removed) using the Mask section.


If you have selected multiple Rooms or Spaces, the same workplane height and point spacing will be assigned to all. You can edit individual members of the selection later if necessary.

Multiple workplanes

ElumTools will only allow a single calculation plane height to be specified at one time when using the Add Calculation Points for a Room or a Space command. If you need to compute points at more than one elevation such as workplane and floor, simply select the command again to add an additional grid, or select the Room/Space in Revit followed by the command. ElumTools will prompt to see if you want to edit the existing point grid, or add new points as shown.

Basic Exterior Use: Add Points - Region

Most exterior calculations in ElumTools will depend on the use of Regions as the preferred boundary type. Regions are well suited to exterior lighting analysis as they can be of any shape, contain holes (no points), and even include multiple shapes. ElumTools can then easily assign calculation points too the entire region in one operation.


Similar to our discussion regarding basic interior calculations above, exterior calculations may only require point spacing and workplane height. The illuminance Metric is selected by default and masking of unwanted points can be used if the region shape does not eliminate that area.


A very typical use case will be the assignment of calculation points to one region which follows the shape of the parking area (our example image), and then the construction of a larger region to contain all exterior geometry to be included in the calculations. The ElumTools calculation command would then be used to select the larger region as the calculation volume.


In some cases there will be calculation point locations that are obstructed by furniture, machinery or structure that you wish to remove from the calculation. This is called "masking". ElumTools will allow points to be masked by selecting the objects that will create the mask, or by Revit Category such as Furniture. Please refer to the separate topic titled Masking Calculation Points for details.


Lighting Metrics

Calculation point locations can be used for the computation of a number of different lighting metrics, and multiple metrics can be assigned to the same Calculation points instance. To date, these metrics are: Illuminance (E), Diffuse Luminance (L), Luminous Exitance (M), Unified Glare Rating (UGR), Daylight Factor (DF) and Photosynthetic Photon Flux Density (PPFD).


Assign the lighting metrics by opening the Metric section of the Calculation Points dialog and checking the appropriate boxes. Your selection can be changed if necessary using the Edit Points command. When the software is set to Horticulture mode the default metric will be PPFD.


When you select a calculation option in ElumTools, all Metrics are computed. You can change which metric is visible from the ElumTools toolbar (Metric menu). All statistics are a property of the Calc_points family once the calculations are complete.


Calculation Modes

By default, all four of ElumTools calculation Modes will be enabled for each calculation grid you place: General Use, Emergency, Daylighting and Horticulture. This simply means that if you are going to run Emergency or Daylighting calculations for the selected boundary, you don't have to enable these modes separately, it is already done. However, if you don't plan on using these modes for this particular boundary, but you do plan on using them for other boundaries (Emergency Mode for example), then you might elect to remove the check marks from the appropriate modes so they do not compute. This saves time and may make your work cleaner as you won't have meaningless results for areas you are not interested in.


The View button to the left of each metric controls the visibility of the calculations relative to that mode in the right side of the dialog. General Use is enabled by default.


Area Based Options (or Point Options)

The Area Based Options section of the dialog provides settings to tailor your point specifics more carefully. This section may also be titled "Point Options" when interacting with Projected calculation points. You may only need this section occasionally depending on your lighting application. The point spacing and workplane height entries are redundant to those under the General section that is open by default.


Spacing (Columns, Rows) - This is provided in the event you want to use different point spacing values for rows and columns. In this case, click the lock (to unlock) and change the values.


Shift Points - Shift Points can be used to adjust the locations of the calculation points horizontally or vertically with respect to the local coordinate system to avoid obstacles, or to shift the grid slightly one way or another. The setting must be a number less than the Spacing. Entries greater than or equal to the spacing will be automatically adjusted. NOTE: This is not the same as Boundary Offset which is more often utilized (see below).


Workplane Height / Grid Offset - Enter any number relative to the base elevation of the boundary (Room, Space, Region etc). This is redundant to the same setting in General Use section of the dialog. The default workplane height for commercial lighting is 2.5 feet in US Customary Units and 0.76 meter in the metric system. In the event of Face Hosted points (Planar Face), this is the distance from the face the plane of points will be located.

Boundary Offset - The Boundary Offset will constrain the calculation points within an imaginary polygon the same shape as the selected calculation volume (Region, Room or Space), but offset some distance inside (positive) or outside (negative) of the original boundary. Boundary Offset will consider holes caused by geometry such as columns in the computation of boundaries.



Rotation - This is the angle in degrees specified in a counterclockwise direction from East by which the grid of points will be rotated in the Room or Space. For example, if you prefer your grid points to follow a positive local X axis that is 45 degrees (SW to NE), then enter a value of 45. The text will read along the same local axis of rotation in the ElumTools visualization viewer. However in the Revit view the point locations will remain aligned with the rotation angle, but the text will read vertically (see captures).


Auto Rotate Points - This setting is enabled by default and will automatically rotate the points to align with boundary volumes that are not orthogonal. When disabled (unchecked), the points will be arranged in rows and columns in the XY plane. By selecting the checkbox, the rows and columns will align with the boundary rotation (see example below).

Non-orthogonal room Auto-rotate Enabled
Auto-rotate Disabled


Center Points- The Center Points option will center the calculation point grid in the room or space such that the end spacing (wall to first point) is less than or equal to one-half the specified point spacing. This setting is enabled by default.


Include Points in Holes - By default ElumTools will not include calculation points in voids caused by face-based objects, even if they are disabled in settings. Points in these areas can be enabled by selecting this parameter.


Include Points on Boundaries - You have the option to include rows or columns of points that fall directly on the boundary of the calculation volume. As an example, consider the crease between the floor and wall. Points on Boundaries are theoretically undefined as they lie in the crease. However, ElumTools may, or may not include these points depending on rounding error. For example, a wall may occlude some points but not others. Typically, boundary points are not desirable on interior surfaces that are adjacent to other surfaces such as floor adjacent to a wall. They may be useful on surfaces that are free standing, such as an exterior region.

Points centered, no offset, Boundaries unchecked

Points on Boundaries, not centered,

no offset. Notice the origin of grid is in the upper right corner.

Points on Boundaries, offset of U=1', not centered. Again, with origin in the upper right corner, the U offset of 1' moves the points to the left by one foot.



Select Reference Point

If you require a specific reference point for your calculation grid, use the Select Reference Point command to locate this point. After clicking the button, ElumTools will return to Revit to allow you to select any point. This point is most likely going to reside inside the calculation volume (Room, Etc.), and is often most easily thought of as one of the corners of the grid. Calculation points will be spaced accordingly from the reference point. Optionally, you can elect to use the "Include Points on Boundaries" and "Shift Points" settings to align the points to meet your expectations. You can clear the reference point using the Clear button.



Aiming (lightmeter)- Many lighting calculations are direction-specific. That is to say, if the light meter or photocell is aimed in a specific direction, it will be able to measure only light incident from sources within a hemispherical view of the meter normal. For this reason, it is necessary to be able to aim the light meter to compute different specifiable metrics, such as vertical illuminance in a specific direction, or "At Point" illuminance where all light meters face a specific location in XYZ space (as in a TV camera). UGR is also a direction-sensitive metric and requires the lightmeter be aimed vertically in one of the compass directions analogous to the observer viewing direction.


There are a variety of light meter settings in ElumTools, enabling easy setup for the desired calculation.


HINT: It is helpful to zoom in to the graphics area of the dialog to see the meter aiming vectors. You may need to change the viewing to "Perspective" from the Viewpoint menu.


Light meter Aiming


Calculation Point Name Synchronization - Calculation points associated with Revit Rooms, Spaces, Areas, and Regions, will synchronize their name with the Revit model name by default. For example: for a Revit room with name of Room 1, the default calculation points family name will be Room 1 as well.


Changing the Room, Space, Area or Region name in the Revit model will automatically update all associated calculation point names.


You can change the calculation points name if desired by entering your own text in the Name cell. ElumTools will no longer synchronize that name with the model. A button below the Name cell is provided to allow you to resynchronize with the model anytime.

When opening a model saved using a previous Revit version, ElumTools will check for calculation points names that are out of synch. You can elect to synchronize them all at that time or leave them unchanged.