Unitize for Revit Review: Automated Residential Layout Generation Inside Your BIM Workflow

Unitize for Revit is a free generative design plugin developed by London-based Matterlab that automatically generates residential floor layouts from building masses directly inside Autodesk Revit. Originally commissioned by Make Architects, the tool targets the repetitive feasibility analysis phase of residential projects, where architects typically cycle through dozens of massing and unit mix iterations before landing on a viable scheme.

What Does Unitize for Revit Actually Do?

At its core, the unitize revit plugin solves one specific problem: it fills building masses with residential unit layouts so architects can evaluate feasibility in seconds rather than days. The traditional residential design workflow involves creating a building volume, manually fitting apartment units inside it, calculating the resulting unit mix, and then repeating the entire process when the mix does not match the brief. Unitize automates that middle step.

You start by modeling a conceptual building mass in Revit. The plugin currently supports most standard residential building forms, including L-shaped, I-shaped, C-shaped, H-shaped, and E-shaped configurations. Slanted roofs and stepped masses are also supported. Once your mass is ready, you open Unitize from the Add-Ins tab, select the mass using the Mass Selector tool, and define your parameters: desired unit mix percentages (studio, one-bedroom, two-bedroom, three-bedroom), floor-to-floor height, and whether you want a stacked or randomized floor unit layout.

The analysis runs instantly. Unitize returns the total number of units broken down by type, total area, number of floors, building height, mass efficiency percentage, and core count. If the results do not match your target, you adjust the mass or the inputs and run it again. When you are satisfied, clicking “Create Units” generates the actual unit geometry inside your Revit model. You can also export results as a JSON file for further processing.

How the Unitize BIM Workflow Fits Into Feasibility Studies

Residential feasibility studies follow a predictable loop. An architect assesses a site, considers planning constraints (density limits, height restrictions, council requirements), generates building volumes, and then works out how many units of each type fit inside those volumes. The resulting mix rarely satisfies the brief on the first attempt. This loop can repeat dozens of times across multiple mass configurations before a competitive bid is ready.

Matterlab built Unitize specifically to shorten that loop. According to RIBA Journal’s coverage, the plugin can reduce feasibility assessment time by one to two days per iteration. Kent Burns, project technology expert at Make Architects, described the advantage: the plugin allows the team to carry out more iterations, assess masses faster, and get immediate feedback on what a given volume could yield. The speed improvement comes from keeping the entire process inside Revit rather than requiring architects to switch between separate tools and convert file formats.

Before Unitize, Make Architects relied heavily on Excel spreadsheets to calculate unit counts from building masses. That manual approach was time-consuming and error-prone, particularly when the design team needed to evaluate multiple massing options in parallel. The integrated BIM environment that Revit provides makes it possible for a plugin like Unitize to read mass geometry, generate layouts, and feed results back into the same model without any data translation step.

Setting Up Unitize in Revit: Step-by-Step

Getting started with the unitize automated layout generation tool is straightforward. Matterlab released Unitize as a free download after initially offering it as a commercial product. The company made this decision to support architecture firms during a period when competitive bidding pressures were particularly intense. To install:

Download the installer from the Matterlab Unitize page. Run the setup and follow the prompts. Once installed, Unitize appears in the Add-Ins tab of your Revit toolbar. Open a project with a conceptual building mass already modeled. Click Mass Selector, then Add Mass, and select your target mass in the canvas. The selected mass will highlight, and its Element ID and name will appear in the Unitize sidebar.

From there, set your unit mix percentages and floor-to-floor height. Unitize calculates results immediately. You can adjust inputs, reshape the mass, or add additional masses at any time. The interface updates in real time, which is where the speed advantage becomes obvious compared to spreadsheet-based workflows.

If you are new to working with masses in Revit or need a refresher on BIM fundamentals, our guide on Revit for architecture students covers the core concepts you will need.

Supported Building Shapes and Current Limitations

Unitize works with the most common residential massing shapes: linear (I), L-shaped, C-shaped, H-shaped, and E-shaped forms. Stepped masses and buildings with slanted roofs are also handled. However, the tool does have clear limitations that potential users should understand before relying on it for complex projects.

Non-standard or highly irregular building geometries are not yet supported. Curved facades, freeform masses, and very complex interlocking volumes will not produce reliable results. David Flynn, director and co-founder of Matterlab, has acknowledged this gap and stated that future updates aim to include non-standard shapes and more complex residential configurations such as affordable housing percentages, low-density schemes, high-spec apartments on upper floors, and secondary service cores.

Some architects at Make Architects have described “competing” with the plugin, generating layouts with Unitize and then manually refining them because the tool does not yet handle more detailed room arrangements. This is a healthy way to use it: let the algorithm handle the volume math, then apply your own spatial judgment where it matters.

Comparison: Unitize vs TestFit vs Autodesk Generative Design

Unitize is not the only tool addressing automated residential layout generation. Two notable alternatives are TestFit and Autodesk’s built-in Generative Design for Revit. Each serves a different scope and user profile.

Unitize’s strength is its simplicity and zero cost. If you already work in Revit and need fast residential unit counts from massing models, it does exactly that with almost no setup. TestFit is a more powerful platform with site-level planning, parking optimization, and built-in financial modeling, but it comes with a subscription cost and operates as a standalone application. Autodesk’s Generative Design requires Dynamo scripting knowledge, making it the most flexible but also the least accessible for architects who are not comfortable with visual programming.

For a broader look at how these tools fit into the current landscape, our article on AI architecture design in 2026 covers the full range of generative and analytical tools available to architects today.

Who Should Use Unitize for Revit?

The ideal user is an architect or design team working on residential feasibility studies in Revit who needs to quickly test how many units a given building mass can accommodate. Small to mid-size firms benefit the most because the tool is free and requires no additional software licenses or platforms. Firms responding to competitive bids can use Unitize to run through more massing options in less time, which directly improves the quality of their submissions.

Larger firms with dedicated computational design teams may find Unitize too limited for their needs. If your projects require custom unit types, mixed-use programming, parking optimization, or financial modeling tied to design iterations, TestFit or a custom Dynamo workflow will serve you better. But even in those firms, Unitize can be a useful quick-check tool for junior designers or competition teams who need fast answers without setting up a full parametric model.

If you are still building your Revit skills alongside other BIM platforms, starting with a simple tool like Unitize is a practical way to see how generative design concepts apply to real project scenarios.

Video: Unitize for Revit Demo and Walkthrough

This video from an independent reviewer walks through the full Unitize workflow, from mass creation to unit generation, and discusses potential future development directions for the plugin.

Where Unitize Fits in the Bigger Picture of Automated Layout Tools

Unitize was one of the earliest Revit-native tools to address automated residential layout generation specifically. It arrived before generative design became a mainstream feature in BIM software and before platforms like TestFit expanded into full feasibility ecosystems. Matterlab itself has since shifted focus toward KOPE, a cloud-based toolkit for industrialized construction, which reflects the broader industry movement toward off-site manufacturing and modular building systems.

For architects, the practical takeaway is this: Unitize remains a useful, free, and lightweight tool for a specific task. It will not replace your design process, and it was never intended to. What it does well is remove the tedious spreadsheet math from early-stage residential massing studies so you can focus on the decisions that actually shape the project. If your practice handles residential feasibility work in Revit, adding Unitize to your toolbar costs nothing and can immediately save time on your next bid.

To see how other Revit add-ins can improve your workflow, check our curated list of the most useful plugins across different project types.

For a deeper understanding of how BIM technology is shaping the profession, our article on becoming a BIM expert covers the skills and tools that define modern architectural practice.