Six years ago, business school classmates Sam and Chris discovered their common passion for improving people’s lives with affordable access to solar energy. During their first year at Stanford’s Graduate School of Business, they joined forces to develop a 50kW solar installation for a school in East Africa—reducing its electric bill and providing uninterrupted access to clean energy.
But while the installation took just a couple of weeks to install, they were struck by how long it took to plan and design. Designing a system on the other side of the world, conducting financial analysis, and planning its installation took months!
Realizing how much time and money solar installers could save if they had a way to create accurate solar designs remotely, Chris and Sam founded Aurora Solar in 2013 to make that vision a reality. Since then, the desire to make remote design accessible and intuitive to solar installers—while being as accurate as onsite assessment—has been the driving motivation for the team, and is why we continually focus on releasing new features and functionality. Aurora has pioneered remote solar design, becoming the industry’s most validated and feature-rich solar software.
However, while building an accurate 3D model of a project site is vastly faster and easier than onsite assessment, this process can still be challenging and time-consuming.
Even with cutting-edge tools, like LIDAR and computer vision, there can be trade-offs between speed and accuracy. Getting every detail perfect, in spite of factors like skewed satellite imagery or irregular roof structures, can require additional time or skill, and creating a quick, simplified design might sacrifice accuracy. But what if there was a way to eliminate these trade-offs?
To create the industry’s most intuitive solar design program, Aurora set out to reinvent the process of constructing a roof model, rethinking it from the ground up. This is the story of Aurora’s invention of SmartRoof, a tool that reimagines solar design.
Figure 1. An example of the kind of complex solar project site model and design that Aurora’s new approach to remote site design makes possible in just a few minutes.
Rethinking Remote Modeling
How do you make roof modeling dramatically easier without sacrificing accuracy and functionality? Co-founder Chris Hopper has been contemplating this question since Aurora’s earliest days, and for over a year our team has been building a new feature to make this vision a reality.
We wanted to not only make the process of building a site model faster and simpler, but also reduce human error, such as model inaccuracies resulting from confusing or skewed satellite imagery.
Additionally, we wanted to create a tool that would make modeling unusual and complex roofs straightforward. If you’ve been designing solar installations for a while, you know that residential roofs come in a vast array of forms (for definitions of some of the roof terms we use in today’s article see our examples below).
Figure 2. An example of a gable roof (2D left and 3D right) as modeled in Aurora. One of the simpler roof types to model, gable roofs are defined by having just one central ridge line.
The diversity of roof types presents many modeling challenges for solar designers—from basic gable roofs (Figure 2), to hipped roofs (Figures 3 and 4), roofs with dormers (Figure 5), roofs with folds (Figures 6 and 7), and roofs where the ridge line is off-center (Figure 8).
Figure 3. An example of a hip roof modeled in Aurora. In contrast to a gable roof, hip roofs have diagonal ridge lines extending from the corners to the center of the roof.
Figure 4. Hip roofs come in many variations, such as this cross-hipped roof modeled in Aurora.
Figure 5. A house with a dormer (circled in green) modeled in Aurora. Dormers are common roof features that have traditionally presented a challenge when creating a site model.
Figure 6. An example of a Dutch gable roof modeled in Aurora. Also referred to as “attic overhang dormers,” Dutch gable roofs are defined by folds (circled in green) that create the appearance of a dormer.
Figure 7. Another type of roof with folds is a gambrel roof, such as the one above modeled in Aurora.
Figure 8. Saltbox roofs, like this one modeled in Aurora, are defined by an off-center ridge line.
Recognizing the complexity created by the great variety of roof types, we arrived at the idea of a software tool that would be able to infer a roof's internal lines just from its perimeter. In this way, much of the time-intensive work would be done for the designer—eliminating sources of human error, and making site modeling easy and (dare we say it?) even fun.
After over a year of development and extensive user testing, SmartRoof has arrived.
What Makes SmartRoof Different?
SmartRoof introduces several completely new innovations for remote solar design. SmartRoof’s defining breakthrough, never before achieved in solar design software, is its ability to infer the internal roof structure (how different planes and roof sections intersect) just from the roof perimeter and a few inputs from the designer (Figure 9).
Figure 9. SmartRoof infers the internal lines and planes of a roof based on its perimeter.
SmartRoof makes the process of drawing the roof perimeter easier by providing guides and snap functionality to get perfect 90º angles, so inaccuracies in satellite imagery don’t translate into inaccuracies in the 3D model. Additionally, SmartRoof makes modeling multilevel roofs and other complex structures easier by allowing the designer to draw roofs in multiple parts, which are then seamlessly combined.
SmartRoof also makes it much easier to account for dormers and folds, two common but difficult-to-model roof features. With special dormer functionality (Figure 10), you can drag and drop a dormer onto your roof drawing and SmartRoof will incorporate it into the 3D model. With the ability to copy and paste dormers onto different roof planes, designers can save even more time. Similarly, folds—where a roof plane with a certain pitch intersects with a roof plane at a different pitch—have historically been difficult to add when building a 3D model. With SmartRoof, you can easily insert folds (such as the ones in Figures 6 and 7 above) and adjust their location as needed.
Figure 10. SmartRoof’s dormer feature allows designers to drag and drop dormers onto the roof, as well as copy and paste them, for easy integration into the site model.
In addition to Aurora co-founder Chris Hopper, who first envisioned SmartRoof, the core project team included Computer Vision Engineer Matt Stevens and Front-End Engineer Kelly Stevens. After conceiving of the initial idea for SmartRoof and identifying mathematical approaches that could enable this functionality, Chris developed the initial prototype of SmartRoof. From there, Matt worked to refine the underlying algorithm, and Kelly built the functionality into Aurora. Matt and Kelly also worked together to incorporate approaches for modeling dormers and combining different roof sections.
After SmartRoof was developed, extensive user testing was done to ensure that this new approach to roof modeling was accurate, intuitive, and met the needs of both solar designers and salespeople. Among the modifications made based on user feedback were the ability to drag interior edges and folds and pop-ups to make it easier to make adjust the properties of different parts of the roof, like dormers (see Figure 11) or roof faces (Figure 12).
Figure 11. SmartRoof has an inspector function to allow the user to modify the characteristics of dormers.
Figure 12. SmartRoof users can adjust the pitch roof faces or change the height of a roof (particularly helpful when creating models of houses with roofs at different levels).
Judging from preliminary user responses, the final product is already reshaping how solar designers work for the better. Discussing how SmartRoof has impacted his work, Ivan La Frinere-Sandoval of First PV Solar, says:
"SmartRoof speeds up the solar design process tremendously. Instead of drawing the entire detailed roof structure we just trace the perimeter outline and the software detects the interior roof edge details. Incredible!"
Aurora has come a long way since we first started our journey in 2013, but Chris and Sam’s vision of a software program that would make exceptional remote solar design faster, easier, and more cost-effective remains our guiding light. SmartRoof is our latest—but certainly not last—push to expand what is possible in remote solar design.
Interested in learning more about how to integrate SmartRoof into your workflow?
This tutorial provides a step-by-step overview of how to use SmartRoof.