Occupancy Calculations and JavaScript

The other day I read a post at Revit Add-ons about integrating Java Scripts into Revit. I was intrigued by an example it described which provides a connection between a java script calculation (formula) and assigns it to a parameter. A very common request among Revit users is to be able to associate with a formula with a Shared Parameter, and in this case occupancy calculations. Timing is a funny thing because an email came in the same day asking for advice doing these calculations.

The application is called LazJS and is currently offering a beta version 1.0. Fwiw, I created an Occupancy Calculation sample project years ago which you can download HERE. I thought I'd open that project and try LazJS out on it. Since we can't put a calculated value in a tag the example uses a schedule so we can transfer values manually. With the advent of the API there are more options but for anyone who is leery of programming it's still a bit intimidating.

I found it was really easy to get this installed and configure LazJS to fill in the values for me automatically and keep them updated if I make any changes. This is the dialog that appears for their ParamJS tool. I started by choosing the Rooms category. Then I chose the parameter that is in my room tag. Then I dragged the parameter whose value I wanted to be in the tag up to the code editor window. Once the code was present I clicked Run, seeing values in the results window I clicked Save.

Now whenever I add a room and assign a occupancy type its tag fills in the appropriate Occupancy Factor for me (the script does). Same for any editing I do of existing rooms.

Worth a closer look if only for this piece of their whole application.

Occupancy Data Application

I've written about the workaround solution for documenting occupancy information in room tags in the past. I've even shared a sample project file based on the work I did for Scott Davis' past firm WLC Architects in 2005 (before he joined Autodesk). Until the API came along we were faced with a semi-inelegant solution that involved manual data entry and checking before plot day. Even after the API nobody really addressed this issue directly, till now...

Rahul Shah (blog: Revit Sticky Notes) works for Wood Bagot in the UK. He responded to a query at AUGI with a promise to write an application to push a calculated value to make Occupancy information taggable. He posted his solution today on his BLOG.

His written instructions on the blog post are:

NOTE: In order to use this plugin you will have to add "Occupancy Load Factor (as area type)" and "Occupancy Load (as integer type)" shared parameters to your project file and assign them to Room object as Instance. Also, calculated occupany load value is not dynamically linked with other values so if you change room size or occupany load factor then you will have to rerun this tool to update occupancy load value. Please read the Readme.txt file contained in the zip file for more information.

You can DOWNLOAD IT NOW!

Occupancy Calculations

A time consuming task for architects is the evaluation of the project's intended occupancy and its impact on egress from a building. It is possible to improve this process considerably with Revit by reporting data in Room schedules. However simply reporting this same information in a room tag isn't so trivial.

The fundamental problem is that we can not display data that we calculate inside the project in a tag yet. A tag family can not use the area value in an equation because it doesn't exist until you are in a project.

This FILE is an example of a strategy that reduces some of the drudgery of looking up data and having the numbers "crunched" but leaves us with manual data entry to get the information in tags so it can be display meaningfully in plan views as well as listed in a schedule. I did the work in this example but the inspiration goes to WLC Architects, where Scott Davis used to work. It is an imperfect example/solution but should serve as inspiration for your own approach to this issue.

Some of my thoughts about how this might change in Revit:

We need a way to tell Revit that a tag will use a project value, like area, once it is inserted and an object is tagged. A placeholder for AREA that will assume the true value when you tag a space but in the family itself substitutes a temporary value so the formula will "work".

Alternatively we need a system family tag type that can combine instance data like Area with other shared parameters to display calculations.

A third concept might be schedules that actually behave like tags and allow freeform placement of parameters and linework to look like a tag.

Yet another is to allow us to map one parameter to another within a project. Essentially allowing what we have done in these schedules manually to be done automatically, ala Excel...Cell A1 is equal to Cell J4.

In terms of value delivered, this sort of evaluation/calculation is a process that all firms go through to some extent. Evaluating occupied spaces and demonstrating how the design meets the code. This is a business problem Revit needs to help us resolve. Giving us greater ability to decide where and how information will be displayed is very important.

The bottom line is we need a way to display calculated data in tags.