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Envelope: the Origin Story

What everyone in NYC real estate understands: zoning is ridiculously complex

The Zoning Resolution of NYC regulates the shape, size, location, and use of every development in the city. It is the oldest and most complex code in the country, having been built up and layered over every year throughout the last 100+ years. It is now a 4000-page document, known perfectly by nobody, and known well only by a handful of very expensive — and busy, sometime grumpy — specialists. It’s painful to navigate, often taking zoning consultants weeks and thousands of dollars to understand the development potential of a single site.

What we’ve always understood: zoning code is like computer code

Zoning rules are very much like program code: they’re hundreds, thousands of “if-then” statements, layered by district and time and priority. We know that once the rules have been properly coded and interpreted into 3D, a machine can do the computational work of calculating the maximum size, shape, and floor area of an infinite number of scenarios on any site. We also know that computers can radically reduce human error in a high-stakes industry. They can even detect clashes in the rules themselves.

What we did about it: took a deep breath and faced the challenge

A decade ago, SHoP Architects set themselves the wildly ambitious (read: insane) challenge of mapping the thousands of complex NYC zoning rules into an intuitive and simple massing analysis program. Over the years, they built rules into software, in collaboration with Sarah Williams, director of MIT’s Civic Data Design Lab, and one of the world’s preeminent mapping and spatial data experts. They called it Envelope, in honor of the zoning “envelope” — the area in which it’s possible to build. Of course, its double-entendre is “back of the envelope” — the estimated floor area calculation you could get out of a site at the click of a button.

In 2015, Envelope was spun out into a separate company, and our current team of engineers and zoning specialists took over to continue their work and build the logic into commercially scalable software. Our mission was — and continues to be — to build SimCity™ for real life: helping real estate professionals, cities, not-for-profits, community boards, brokers, appraisers, zoning attorneys, and more, visualize and run scenarios on development potential under the rules. The software we’ve now built (and continue to refine) is fully scalable to other cities, incorporates accurate proprietary data, a survey-grade parcel map, corrected zoning boundaries, and many more intricate 3D zoning concepts.

The challenge — and the fun — of our work

Producing a city-wide, accurate, parametric 3D rendering and analysis of floor area potential under zoning requires a cocktail of industry and zoning specialists working with designers, applied mathematicians, and geometry engineers, who — together — determine what’s algorithmically feasible AND what’s practical for users. Our team is made up of experts who are world-class in their fields, and have the capacity to learn enough about the others’ specialties to communicate fluently. They are truly exceptional people, building truly exceptional software — and amazing me, and our clients, every day.

And we pulled it off right here in one of the most complex cities in the world.

Can we help you?




Envelope offers legal-quality zoning analysis and architecture-quality visualization at a fraction of the time and price.

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