Rendering created with Blender Cycles
Cristian Taborda Mejía / 77 Render Studio Rendering created with Blender Cycles

Software is increasingly a top expense for architecture and design firms. With many software applications and file formats becoming de facto industry standards, firms are increasingly tied to commercial software publishers. Many in the software industry have moved from selling software as a one-time purchase—which would remain usable after it was fully paid for—to a recurring monthly subscription model—in which the tool loses functionality if the user stops paying. As a result, companies across industries have seen their monthly software expenses grow. One way that architecture and design firms can alleviate this financial burden and still have access to the software and technology necessary to run their businesses is to explore open-source alternatives, whose numbers have increased in recent years.

Open-source software is released under a specific license that gives users the right to download, use, or change the software and its source code. Unlike commercial software, which typically has a protected source code and proprietary file formats, open-source software projects are not profit-driven and encourage users to modify and share their code with the wider community. Often the goal of these projects is to develop applications that can accommodate multiple viewpoints and ways of working. Some well-known open-source projects include the Linux operating system, the WordPress web publishing platform, and the audio-editing application Audacity.

Open-Source Options

The promise of free, open-source software may sound great, and, importantly, many open-source applications are suitable for the design workflow, particularly as architects take on more digital tasks. Below, I list seven options to consider, ranging from 3D modeling tools to energy analysis applications.

Rendering process created with Blender Cycles
Cristian Taborda Mejía / 77 Render Studio Rendering process created with Blender Cycles

Blender is a free and open-source suite of 3D modeling tools that provides modeling, rendering, animation, and simulation capabilities. Though the suite is geared more toward visual effects and character animation than architectural applications, a community of users offers tutorials and resources for the AEC professional through websites such as Blender3DArchitect. Blender does not directly import proprietary file formats like Autodesk’s DWG or RVT, but it can import open formats such as DXF.

A screenshot with the caption: "GIMP running on Microsoft Windows features a widget theme mimicking the native environment"
The GIMP Team via a Creative Commons Attribution-ShareAlike 4.0 International License A screenshot with the caption: "GIMP running on Microsoft Windows features a widget theme mimicking the native environment"

The GNU Image Manipulation Platform is an open-source alternative to Adobe Photoshop for creating and editing digital images. Initially released in 1996, GIMP version 2.10 does not provide as many features as Photoshop and is known for being somewhat harder to use. However, it has developed a robust user community. GIMP is cross-platform, meaning it works on the Windows, Mac, and Linux operating systems.

What GIMP does for raster graphics, Inkscape does for vector graphics. This free and open-source software lets users create scalable graphic images using the scalable vector graphics (SVG) file format. Similar to Adobe Illustrator, Inkscape provides flexible 2D drawing and text manipulation tools.

Pentagon made with a compass and straightedge on LibreCAD 2.0.0 beta (2013)
LibreCAD user Raulshc via a Creative Commons Attribution ShareAlike 3.0 license Pentagon made with a compass and straightedge on LibreCAD 2.0.0 beta (2013)

The interface and concepts of this open-source 2D CAD application are similar to AutoCAD, making it easy for skill transfer. Unlike AutoCAD, LibreCAD only works in 2D so you cannot create or edit 3D models, and it can only import DXF files. However, files can be exported in several formats. LibreCAD is available in more than 30 languages and, like GIMP, is cross-platform.

Users of the Microsoft Office suite will be familiar with many of the tools included in LibreOffice. This full-featured set of office tools includes applications to accomplish standard office tasks such as word processing, PDF editing, presentation design, and spreadsheet creation. LibreOffice uses the OpenDocument file format, a nonproprietary document format that is also open-source. Unlike Google Workspace, LibreOffice is not cloud hosted, which may be a benefit or hinderance depending on your workflow.

BIM Workbench can be installed in FreeCAD from the Addon Manager.
FreeCAD via a Creative Commons License BIM Workbench can be installed in FreeCAD from the Addon Manager.

FreeCAD provides a robust set of 3D modeling capabilities in an open-source application. It is also a parametric modeling tool so users can make changes by directly editing the model’s history. FreeCAD contains an Arch Workbench that provides BIM-specific workflows within the software. It also incorporates drafting tools in a 2D Workbench for creating traditional 2D documentation and drawings. FreeCAD supports a variety of file formats including DXF, OBJ, STEP, and IFC.

Built on the EnergyPlus simulation engine, this open-source energy modeling solution was originally developed by the National Renewable Energy Laboratory. One of the main benefits of OpenStudio is its SketchUp plug-in, which allows users to create models in Trimble SketchUp and then analyze them in OpenStudio. The resulting analysis can then be viewed directly in SketchUp.

PyRevit add-in for Autodesk Revit
screenshot courtesy Michael Kilkelly PyRevit add-in for Autodesk Revit

Open-Source for Commercial Software

In addition to the stand-alone applications listed above, other open-source projects have been built on top of commercial software. This approach combines the community and transparency of open-source projects with the ubiquity of industry-standard tools and file formats. For example, PyRevit, developed by architect and programmer Ehsan Iran-Nejad, is a popular open-source add-in for Autodesk Revit. While Revit is not free, Iran-Nejad’s add-in is freely available. Users can download the compiled add-in or its source code and modify it to their own uses.

Likewise, Ladybug Tools is a collection of open-source tools that support environmental design. The Ladybug Tools suite works with commercial applications, like Rhino, as well as open-source software such as OpenStudio.

Wind analysis via Ladybug Tools
courtesy Ladybug Tools Wind analysis via Ladybug Tools
Sunlight analysis via Ladybug Tools
courtesy Ladybug Tools Sunlight analysis via Ladybug Tools

Some commercial software companies, such as Autodesk, have also released software under open-source licenses. Dynamo, a visual programming application is available for free as an open-source project. While a version of Dynamo ships as part of Autodesk’s Alias, Civil3D, and Revit applications, the software developer stopped offering it for purchase this past June. Furthermore, Autodesk plans to discontinue and remove Dynamo Studio from its AEC Collection beginning Jan. 31, 2022. However, users will still be able to download a stand-alone, open-source version of the software, Dynamo Sandbox. While this version does not include all the features available in the one that ships with Autodesk’s paid software, users are free to modify the source code as they see fit.

Open-Source in Practice

Despite the predominance of commercial software in AEC workflows, some firms have found a place for open-source solutions in their stack of digital tools. Dan Stine, AIA, director of design technology at Lake|Flato Architects in San Antonio, Texas, says his firm uses Blender as a way to reduce the amount of post-processing required when doing 3D renderings, in particular when working with rendering content and entourage. “Blender is the connector to all this other content that’s available,” Stine says. “It saves us a lot of additional post-processing work after we render the images.”

Likewise, the free nature of open-source software makes it a low barrier of entry to sophisticated tools that might otherwise be difficult to justify within a project’s budget. Lake|Flato, for example, does not often complete wind studies for its projects. However, when required, it often uses Eddy 3D, a free airflow and microclimate application that works with Rhino. While it does not provide as refined an output as other commercial options, it allows the firm to incorporate the results into its design process.

Using open-source applications does have drawbacks. As Stine describes it, open-source software often “takes additional skill to use, as compared to commercial tools that have more robust user interfaces.” Training may also be an issue, as open-source projects often lack the budget or incentive to create well-documented tutorials and resources.

However, for the enterprising architecture and design firm, the free access to such tools makes the learning curve a worthwhile endeavor.

This article has been updated since first publication.

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