About Matt Kincaid

How many Illumination Engineers does it take to screw in a light bulb? Zero. That's the electrical contractor's job... Besides, they probably spec'd LEDs anyway.

Lighting Power Density using ElumTools

Since day one of ElumTools, Revit has coexisted and offered several powerful tools for electrical analysis, including Lighting Power Density reporting functionality.  The latest releases of ElumTools include new functionality to make it easier to leverage Revit’s LPD tools as a natural part of the typical ElumTools workflow.

The Create Schedule command now includes some additional parameters which are associated with Rooms and Spaces.  To take advantage of the new electrical parameters, the first step is to create and configure Spaces in the host model.

Once you have Spaces set up, you need to make some decisions about how you wish to use each parameter.  Here is an overview of the role played by each.

Specified Lighting Load

These are intended to be reporting parameters and are fairly easy to define.  At a high level, the Specified Lighting Load parameters are values that are simply entered by the user as a design goal.  They are in no way connected to the Lighting Fixture families which are actually placed in the model.

Specified Loads are defined in the Electrical Instance Parameters of each Space.  See below.  Space Lighting Loads can either be specified “By Space Type”, particularly handy for code compliance evaluation, or individually on a per Space basis.

Actual Lighting Load

Actual Lighting Load is intelligently determined by Revit, based on the Luminaire family instances actually placed in the model.  This is intended to help ensure final design proposals meet the design specification and applicable electrical codes.

For Actual Lighting Loads to calculate as expected, all luminaire families must have a properly configured Electrical Connector.  This is a somewhat complex area and will be the subject of a future blog post. Conveniently, however, all of the families in the Built-in ElumTools library have the Electrical Connector set up “out of the box”, as of version 2018.4.

The luminaire families ship with a default load of 0VA, since each family could potentially represent many kinds of fixtures (with very different loads).  To get accurate LPD numbers, the user simply needs to define the Apparent Load Type Parameter appropriately for each fixture Type.


For Revit to compute the Actual Lighting Loads, the appropriate checkbox must be checked in the Electrical Settings. Otherwise, all Actual Lighting Loads will be reported as zero.

Computation of Lighting Loads can sometimes be a performance intensive process.  Therefore, it can be convenient to disable the load calculation functionality when working with larger models and/or on slower systems.



Luminaire Family Validation Made Easy

When a calculation is invoked, ElumTools automatically checks all Lighting Fixture families in the environment to determine whether the family has valid photometry applied.  If the program detects luminaires without photometry it throws a handy warning, alerting the user of the problem.  This is especially helpful for newbies as a quick check to see whether or not all the families are in order.

However, sometimes this warning will be triggered at times when the user actually intentionally doesn’t have a  photometric file assigned.  Take the case below.

In this case, ElumTools is warning the user that it found 4 table lamps (60 W Incandescent) without valid photometry assigned.  For most serious illumination engineering projects, this is what you want (a table lamp typically won’t be an integral part of a commercial lighting solution).  Often these kinds of families will be included in the Revit project for Rendering purposes, but are not germane to quantitative lighting analysis.

What to do?  You could of course click the “Do not show me this again” check box.  But that is a global change that will prevent the warning from popping in all cases, not just this particular one.

The latest releases of ElumTools now allow the user to “approve” individual Luminaire Types directly in Luminaire Manager.  This lets you suppress the invalid luminaire warning on a case-by-case basis.

By default, ElumTools will throw a warning for all Luminaire Types which show a “Red X” in Luminaire Manager (the way it has always worked).

Now, Luminaire Manager also gives the opportunity to click the “red X” and change it to a more friendly “green X”.  Family Types with green X’s still do not contain valid photometry.  But ElumTools will interpret them as “approved” and will not show a warning.

Similarly, you can also approve Luminaire Family Types which DO have valid photometry assigned.  This has no effect on the behavior of ElumTools (apart from changing the icon in Luminaire Manager) and is simply convenient for documentation.  It is in no way a requirement to approve Luminaire Types prior to calculating.

Behind the scenes, ElumTools stores whether a Family Type has been approved, as a shared parameter called “ElumTools Validated”.  This can be easily scheduled which can serve as a quick way to see which families still need validation (particularly useful on large projects).  Revit even provides some conditional formatting tools to pretty things up.  What fun.

What’s new in 2018.3 (2017.6 and 2016.10 too)

The latest generation of ElumTools is packed with new features, mostly geared to exterior lighting analysis, with some interior applications as well.  The most powerful new feature is the ability to visualize lighting results using isolines and spatial maps.  The video below gives an overview of the feature, along with some tips and tricks.

This release also includes a set of pole mounted luminaire families for use in exterior projects.  Each family can be easily configured to model most common arrangements and the photometry can easily be swapped.  These families solve many of the difficult problems related to nesting the light source as well as building families with multiple sources.

Luminaire Manager also got a face lift, designed to make families with nested light sources easier to work with.  Now you can duplicate, rename, and delete Family Types right in the dialog, reducing the need to go back and forth between Revit and Luminaire Manager.  This can be a big time saver.

Revit 2017 and 2018 users will also be happy to learn that the latest update removes the nuisance “Unsigned Addin Warning” which required users to trust ElumTools at the beginning of each Revit session.  This was accomplished by adding a digital signature to the ElumTools installer and program files, which has the added benefit of improving security and reducing vulnerabilities.

A complete list of changes can be found in the latest Release Notes.

Why Can’t I Suppress the Rendering?

Often when using ElumTools, you won’t be interested in a rendering and will only need the point-by-point illuminance values, and perhaps the associated statistics (avg, max, min, ratios, etc.).  A common question we get is if there is a way to suppress the rendering and have ElumTools only return the numerical results when calculating (usually in the interest of faster calculation times).

The answer to this question is no.  But it isn’t because we neglected to add the feature :).  ElumTools, like AGi32, uses a process called radiosity to consider all the interreflected light and its contribution to the point-by-point results.  With radiosity, the math to produce the calculation point values is identical to the math required to produce the rendering.  In other words, the point-by-points are a by product of the rendering.  So, were the option to suppress the renderings given, the calculation time would remain roughly the same.

There are, however, some things you can do to speed things up, particularly if you are daring enough to compromise on calculation accuracy.  This help article contains some handy tips. These can be particularly useful during design iterations when only approximate computations are required.  Then the settings can always be ratcheted up for final deliverables, when greater accuracy is needed.   Layout assistant can also be a useful “quick calc” tool to get a rough idea of fixture quantities, early in the design process.

Layout Assistant as a “Quick Calc” tool

The Layout Assistant is an easy avenue to quickly estimate average illuminance levels and make adjustments to luminaire quantities as needed to meet your criteria.  To start, simply enter the quantity of luminaires you plan to use.  Layout Assistant will immediately display an average illuminance estimate for the quantity entered, as well estimates for plus or minus 1 luminaire.  layout-assistant-quick-calc-1

The estimation algorithm used to produce the estimate is significantly more powerful and accurate than the Zonal Cavity based methodology built into Revit.  Layout assistant employs the same radiosity engine used by the calculate commands , and estimates results quickly by applying a very coarse mesh to the environment.

There are many options in the Layout Assistant dialog to tinker with the luminaire positions.  When you’re happy with your layout, place the luminaires in the Revit model by clicking “ok”. If you want more confidence in the illuminance estimate first, perform a full calculation using the “Calculate” button.

New Commands Available in 2017.3, 2016.7, 2015.10!

The latest ElumTools update includes dramatic new capabilities to use 3D views to sort the portions of the model you wish to compute. You can now compute the Active view, or compute any number of separate 3D views using the Calculate Multiple Views command. These commands allow easy and intuitive control over which elements are calculated. This is particularly handy for phased projects and projects employing multiple Design Options.


The Calculate Views functionality paves the way for another new command, Create Daylighting Views which will allow you to stratify your model into interior and exterior geometry thereby solving the old problem of exterior geometry in daylight calculations.  Now exterior shading devices and adjacent structures can be considered with ease for Daylight Analysis.


In addition to the new calculation functionality, the latest ElumTools update contains many other Enhancements and Bug Fixes, improving both usability and performance of existing ElumTools features.

Calculation Points on Stairs

Stairs present an interesting challenge when placing calculation points in ElumTools.  Adding area based points, such as space points or region points, isn’t a good option because the calculation grid will be flat.  Planar face points also present a challenge as they would necessitate adding a separate calculation grid to each tread of the stair case (flexible but tedious).  These challenges make stairs a good candidate for line based calculation points.  Here’s a sample work flow.

  1. Create a Reference Plane following the profile of the stairs.  This will typically be easiest in a Section View.
  2. Draw a model line on the sloped reference plane.  This is typically easiest in a Plan View.
  3. Add line-based calculation points to the newly created model line, and use offset lines to create the grid.

Typically for stairs, you will want to define a tight point spacing to be used along the run of the calculation line. Offset lines can then be used to place points along the horizontal span of each tread.

Screen Shot 4

When calculating the stairwell, you will see the calculation points follow the profile of the stairs based on the spacing specified in the Add Points dialog.  Some iteration may be required to get points located in the necessary locations, particularly for complex staircases.  But by using line based points you will save the time of having to locate a separate grid on each tread.

Screen Shot 5

See the video below for an illustration of the steps described above.

Masking Calculation Points

ElumTools now allows calculation points to be associated with both Filled Regions and Areas.  That’s right. It is no longer a requirement that the calculation points be associated with the Room or Space being calculated.  Instead, the calculation points grid can have any shape. This provides an easy mechanism to exclude calculation points from portions of the grid that do not require analysis.

This flexibility can be useful in situations where large equipment or furniture is present.   An easy work flow for this situation is to,

  1. Create a Filled Region or Masking Region, leaving a hole for the equipment.
  2. Add Calculation Points to the Region using the ElumTools command.
  3. Calculate the Room as usual. ElumTools will place points only within the boundary of the Region, while still calculating every element in the Room.  This ensures that all equipment will be properly considered for the Calculation, but calculation statistics will not be skewed due to objects occluding light reaching the calculation work plane.




Calculation Point Family Management

Every time a calculation grid is added to the project, ElumTools places an instance of the ElumTools Calculation Points Family into the Revit model.  This can be a useful visual indicator to determine where calculation points have been placed.  However, it is sometimes convenient to hide the Calculation Points Family.  This can be done using the Toggle Calc Points Family Visibility command as shown below.


The main caveat is the command will not hide the family if the active view has a View Template applied. You are instead greeted with the tool tip below and the Calculation Points Family remains visible.


What to do? Any View Template can be modified to hide the Calculation Points Family. The family is in its own subcategory and can be hidden, just as any other subcategory can be hidden in Revit.


Now suppose you’d like to hide the Generic Models category, but leave the ElumTools Calculation Points subcategory visible.  This can easily be accomplished by a few clicks on the Filters Tab of the Visibility/Graphics dialog.

Step 1. Enable Generic Models in Visibility/Graphics.


Step 2. Create a new Filter.

Create a Filter that hides all Generic Model families whose Family Name does not contain the string “ElumTools”.  This methodology can be applied to either a View Template, or the Visibility Graphics settings of any View in the Project.

Filter Dialog2

Duplicate Linked Models – a cautionary tale

Revit has an interesting feature that allows you to load duplicate linked models with the same name.  This can be useful in some situations but is often a consequence of a simple oversight.  This can sometimes cause problems, and is best understood through a visual example.

Design Tree

This can lead to problems in many parts of Revit and often isn’t a recommended workflow. One such problem you may encounter when using ElumTools is the inability to correctly specify Material Mapping settings. See below.


One solution to this problem is to define all nested linked models as “Overlays” rather than attachments. When nested models are defined as overlays, Revit only locates one instance of each linked model in the host file, which is typically desirable behavior.