TestFit: Gurban

Easily solve surface-parked site plans with TestFit

When we launched Residential Engine (TestFit’s predecessor) we had never imagined that we would have made it this far. It started as a way to solve some technical problems for site planners then blossomed into the most powerful building configurator software available on the market today.

Residential engine unit mix terminal application from November 2015
The unit mix terminal application from November of 2015

Major Low Density Features

Since 60% of new units built today are surface-parked, we decided to work hard on a solid surface-parked algorithm. It solves parking ratios, and generates realistic solutions for the lower-density market.

The major parameters for surface parked site plans include the following:

Parking stall parameters (width and depth)

Parking stall parameters (width and depth)

Drive aisle parameters

Drive aisle parameters

Turn radius parameter

Turn radius parameter

Maximum stall run parameter

Maximum stall run parameter

Internal green buffer parameter

Internal green buffer parameter

Just want a parking lot? No problem

Solve surface parking with TestFit

Other meaningful features

Saved Views

Save three dimensional views in TestFit

Helpful Tool Tips

TestFit tool tips

TestFit on Generative Design

Schemes Tool Testfit to compare site plans

A good friend, Anthony Hauck, wrote an exhaustive explanation of what generative design is. I will stick with his definition of generative design (stand on the shoulders of giants, right?).

Generative design is the automated algorithmic combination of goals and constraints to reveal solutions.

We are a practical startup. We build tools users can use right now and can implement into their workflow today. Over the last 2+ years of working on TestFit, we have been incrementally working towards building-level generative design. Along the way we took some detours for our customers and built things like manual mode, the unit editor, and multiple sites. But the long-term goal has been building-level generative design.

Introducing Schemes

With TestFit, our thinking was to create one quality scheme, and to do it in a few milliseconds. This way users could rapidly prototype different schemes. One thing that our users requested was the ability to compare different schemes easily. With our schemes tool, users can now do that!

Schemes Tool Testfit to compare site plans

Filtering Schemes

Invariably, when presented with more than a few options, it becomes hard to sort out what is good and what is bad–and we have a hard limitation: the human mind can really only compare four things at once. This is why data-driven design tools typically have a parallel coordinate graph to filter out solutions that are not ideal, and to present a narrow range of options. We have built our own parallel coordinate graph, comparing design, zoning, and financial information.

parallel coordinate graph, comparing design, zoning, and financial information

Automatically Generating Schemes

The blueprint for this started with the first version of TestFit. With the 1.0 update, we launched presets. Presets enable users to create their own lists of parametric values, and to simply click between them (think 5 over 2 or type III wrap). TestFit also has a feature called options, which are simply different building mass layouts for the site. The cross-product of “presets” and “options” revealed that there were already several schemes available for users. Here is what automatically generated schemes looks like:

Automatically generated schemes in TestFit

We think, for starters, that 64 schemes should be more than enough. We currently exist in a world where fewer than three schemes are ever test-fitted per site. With a 20-fold increase, we should be able to find more opportunities to solve real estate deals, or at least the data to kill them.

Generative Design for Parking Garages

Generative parking

Why build generative design for parking garages? What do we build most in this world? Parking… What do we hate most in this world? Parking… How many stalls have you counted in the last 30 days? Too many.


Parking can be 20% to 70% (by area) of any project that is built. It’s almost shameful when half of your project is parking, but here we are as a culture–there are 8 parking stalls for every 1 car in this country. Parking is a basic need for any building to be successful–so we design it, build it, and tolerate it. The more efficient the parking solution, the better. This means attempting rectangular garages, parking on ramps, and a stall average south of 400 square feet per stall.

Basic Parking Garage Parameters

  1. Stall Depth – We default to 18′ (we are based in Texas, after all)
  2. Stall Width – We default to 9′ (see reason above)
  3. Drive Aisle Width – We default to 24′ (trucks are large)
  4. Max Ramp Slope – We default to 6%
    • Building code in all of its glory mandates a maximum of 6.66% slope (15 feet of run for every foot of fall). This limits your ability to squeeze stalls, but for a good reason (the guys writing the code were thinking about people in wheelchairs?).

Basic Parking Garage Objectives

  1. Draw the stalls given the user’s inputs
  2. 95% of the garage drawn (in milliseconds)
  3. What bay configuration yields the most parking stalls
  4. What ramp location kills the fewest stalls
  5. Fill any irregular shape with parking

The TestFit Generative Design for Parking Solution

These features are now live within the main TestFit app. For future features to do with parking? We are considering speed ramps, spaces within the garage, entry and exit locations, angled parking, and directional routing. Our intent is to give the industry a tool to solve 80% of garages, and do it in milliseconds.