The biggest real estate construction tech story last year was Katerra’s raise of $865 million to finance the company’s explosive growth. Beyond the sheer size of the funding, the investment is notable for the bet it represents on the scalability of off-site construction.

The concept of off-site construction was popularized more than a hundred years ago when Sears, Roebuck and Co. made “Sears Modern Homes” available through mail-order. A century later, off-site construction may finally be getting its due. Thank technology for that—no single software but the range of applications that make design, preconstruction, fabrication, and installation of off-site constructed components possible on a large scale.

In Katerra’s case, off-site construction is being used to produce prefab, largely modular buildings and modular volumetric building components.

In the near term, modular is indeed the biggest opportunity. Writing on Forbes.com, Alex Radosevic, founder and president of Canon Business Properties, notes the impact of technology on the construction industry is “especially evident in modular. Factory-made steel modules outfitted with the latest electrical and plumbing systems and even high-end finishes and facades now can be transported and then stacked on-site with remarkable precision. Remember Legos?”

Of course. Radosevic goes on to speculate that modular construction may also lead to less reliance on highly skilled workers, which he says can lower the risk of human error while simultaneously reducing labor costs. Radosevic cites the multifamily and hotel sectors as particularly prone to benefit from off-site modular construction right now.

But the story doesn’t end there.

In fact, it’s fast evolving. The very definition of prefab is changing. Historically, “off-site” and “prefab” often have been used in conjunction and interchangeably, with both terms connoting designs and components that are standardized, sometimes off-the-shelf, pre-conceived in advance of a job, and made to fit on a particular site. Think round peg in a round hole, but also round peg in a square hole.

That is changing.

The digitization of construction, including design, preconstruction, fabrication, and installation, now allows off-site construction to be deployed to create even custom components that are not known until after the design of a facility interior or exterior is complete. Think postfab versus prefab.

Let that sink in. Today, off-site fabrication is being used to produce building components after the design has been fully baked using technology. That’s a different application of off-site fabrication—what I’m calling postfab. Net-net, design integrators today are fully fleshing out 100% of the design, and then using off-site construction to produce custom components that are neither standardized nor cookie-cutter.

As a specialty contractor that integrates the services of architects, engineers, general contractors, sub-trades, and off-site fabricators, we know. We deploy off-site construction in our business at Vantis in Northern California to produce custom commercial interiors for high-performing facilities: healthcare, education, corporate office, and more. It is our preconstruction team’s responsibility to guide the process to ensure the entire project can be built using off-site construction before fabrication begins.

In a postfab world, off-site construction can be used to fabricate custom components, including wall assemblies and ceilings, with less waste and off-gassing than conventional construction, and designed to be more easily reconfigured to meet users’ future needs. Thank you, technology, and the dreamers who made it possible.

Consider how far PropTech has come in just the past five years:

“Construction firms have begun to transform and boost their productivity by embracing the digital age. New workflow and productivity applications, augmented by reality design, sensors for material management, drones, and virtual reality devices have started showing up on jobsites as contractors begin to deploy digital solutions across their organizations. Software solutions, including BIM (building information modelling), that have been used for decades have started to become more ubiquitous and advanced, while newer cloud-based software workflow solutions…are becoming industry standards for managing projects.” So concludes Navitas in a recent industry report.

The digitization of construction, including advanced construction modeling and software, enables project managers to capture design intent, price a project, and scope the fabricated components down to last nut and bolt. This includes interior wall framing, finishes, glazing, millwork, doors, and hardware. Plus in-wall and above-ceiling electrical, information technology, audio-visual, low-voltage, and plumbing—everything needed to effectively deploy off-site production in the context of custom commercial interiors.

The net result? Technology allows for smarter, more comprehensive designs for custom components that can be produced off-site to exacting specifications and assembled on-site with laboratory precision.

Yes, off-site construction isn’t just for prefab anymore. The age of postfab has arrived.

Ryan Ware is cofounder and vice president of construction for Vantis, based in Santa Clara, Calif. With more than 20 years in the design and construction industry, Ware has spent much of his career focused on alternative contract delivery methods, design assist with subcontractors, and alternative fabrication methods.