Skema: Jumpstarting BIM

Skema is a new web-based conceptual design tool for architects that aims to “fast forward” the traditional design process to get to the BIM model. It does this through a lot of automation, starting with creating the massing model of a proposed design on a selected site, analyzing it for sustainability, refining the mass with blocking and stacking for schematic design, and finally, converting the schematic design to an LOD350 BIM model which can then be further developed in a full-fledged BIM application like Revit (Figure 1).

I was introduced to Skema at the AIA 2023 Convention last summer and provided a brief overview of it in my article on the conference. I have since had a chance to explore it in more detail, including learning about the recent enhancements that have been added to it.

Site Selection and Massing

Once you log into Skema — being a web app, Skema is accessible from any browser — you can create a new project by specifying the address where it will be located and sketching out the site boundary on the map that is pulled up. You can also select the extent of the site context that is needed. It will then be created in 3D with the topography and massing of the existing buildings coming from GIS data sources like Open Street Map. The site can be further refined in Skema by adding offsets and streets, deleting existing buildings, and adding a background image if required.

Once the site has been defined, you can quickly create the building mass or masses by using polylines or polygons for the base and specifying the number of floors and the floor heights. Push/pull is supported, which makes the massing process more intuitive. A project can have multiple buildings, and a building can be sliced into multiple blocks. You can assign a use type at each level of the massing model: for buildings, for blocks, as well as for individual floors. This is helpful for analyzing the broad space usage at the massing level (Figure 2).

Some additional abilities Skema provides at the conceptual design stage include the ability to save multiple options for the design in order to explore different alternatives (Figure 3) as well as analyze the different massing options for aspects like sunlight and daylight (Figure 4). This analysis is enabled by an integration with the Cove.tool sustainability platform. Cove.tool is also web-based, and Skema’s integration with it serves to highlight how different web applications can connect with web services and work with each other’s data as required, without the need to import and export files or install any software.

Blocking and Stacking

The next step in the design process, after the massing phase, is blocking and stacking — laying out the different spaces on the individual floors of the building. This is where the real power of Skema kicks in.  You can select an individual floor, or an entire block with multiple floors, and apply a layout template to it, which will automatically create the specified mix of spaces on that floor, laid out correctly. So, for instance, in the example shown in Figure 5 which is of a residential building, all the apartment units are configured with their exterior windows facing outside and their entry doors opening into the circulation corridor that runs throughout the length of the floor.

These layout templates are collected in a “catalog” that is displayed in a panel on the left, as shown in Figure 5. These catalogs are specific to a firm, based on their previous work for that type of project. They are created by the Skema team using a proprietary pattern recognition neural network technology that has been pre-trained for a specific building type. It needs to analyze only a few of the firm’s Revit files of that project type to abstract them into “solvers” that can be applied to new projects of that type (Figure 6). These solvers have rules governing aspects like adjacency, connectivity, circulation, egress, minimum and optimal spatial dimensions, and so on, which allow them to intelligent “fit” the desired space types into a layout such that the spaces are appropriately sized and arranged within the floor boundary.

Needless to say, this kind of approach to automating a design would best apply to project types with mostly repeating units such as residential buildings that have apartments, commercial buildings that have offices, school buildings that have classrooms and labs, health clinics that have patient rooms, hotels that have guest rooms, and so on. Thus, Skema is not aiming to be a general-purpose conceptual design solution; instead, it is targeting those buildings — which comprise close to 50% of all new construction — that have repeating patterns that can be automated at the back end.

The automated blocking and stacking layout generated by Skema can be adjusted if required, as shown in Figure 7. (This is a recent enhancement to the application.) Any of the units that are automatically placed can be deleted or moved around and new units from the catalog can be selected and inserted. The units are like puzzle pieces that snap to walls and to each other, making the manual adjustments easy to do.

If there are repetitive floors in the design, you can design one floor in Skema and apply that layout to the other floors (Figure 8). In addition to this being much easier to do in Skema than in a BIM application like Revit, this has the advantage of being much faster. This is because a floor layout is treated as a template that can be applied to other floors, so if any change is made to the template, all the floors are automatically updated. At the same time, any floor layout, even if it was created from a template, can be edited, as shown in Figure 9, where a part of the lowest floor of the building is being designed for parking.

In addition to the broad space usage that could be seen at the massing level (which was shown earlier in Figure 2), a detailed breakdown of the metrics of the project after the blocking and stacking process can also be seen, as shown in Figure 10.

Exporting to BIM

Once the block and stack of the design has been satisfactorily solved, it can be exported to BIM. There is an option to generate an LOD350 preview of the model, as shown in Figure 11. What this is essentially doing is taking each abstracted element of the design and reconstituting it to its full-fledged Revit data. Thus, it is reverse engineering the process by which the Revit designs were abstracted into catalogs for blocking and stacking in the first place. The quality of the data is high, as the reconstitution is coming from the actual element types and families that the firm — the specific Skema customer for which the catalog was created — has been using in its Revit projects for that building type.  

As the final step, the LOD350 model from Skema, if it is okay, can be sent to Revit, as shown in Figure 12. The integration is through an API, and the export is completed in minutes. In this specific project, the podium of the building was created in Revit but the rest of the design — the repeating floors of apartments — was done in Skema and exported to Revit.

It should be noted that with the recent ability to edit an automated layout in Skema, the podium could also have been designed in Skema, as shown in Figure 13, and then exported to Revit.

Analysis and Conclusions

The objective of Skema is to provide a simple and easy-to-use web app to create conceptual building designs that can be simulated and validated, and then to be able to quickly create high-quality BIM data from it. The goal is not to make a 100% complete building; rather, it is to provide a fast-forward button for the repetitive 40 to 50% of buildings which have patterns that can be automated at the back end. The LOD350 model that is automatically generated saves weeks of time that would be spent modeling the building in Revit. Essentially, you don’t have to start over as you would have to do with a conceptual design tool like SketchUp or Testfit.

The value proposition of Skema from a business perspective is that it not only handles the front-end design piece by allowing more considered options for better design proposals in less time, it can also save the time in producing the detailed deliverable once a firm wins the project. By handling the repetitive layouts for programmatically-driven buildings such as apartment buildings, office buildings, health clinics, schools, hotels, and the like, grunt-work is reduced and designers can be freed up to do more value-added work with their time.

I found Skema very easy to learn and use, with a very useful onboarding guide which was a pleasant surprise given how new the application is. The only limitation I could discern at this stage was that Skema is very Revit-centric, with Revit files being used to derive the layout catalogs for a firm that are used for blocking and stacking, as well as the one-click export of the LOD350 BIM model that is limited to Revit. The tighter integration of Skema with Revit than with other BIM tools was not a surprise, given that the founders of the company have their roots in Revit. However, since Skema is not built on any Autodesk technology, future versions of the application should be able to work well with other BIM applications as well. Perhaps, Speckle might be the way to go? (See the recent article: SpeckleCon 2023: AEC Implementations and Speckle Add-ons.)

BIM has been great as a more intelligent way to design and construct buildings and infrastructure, but we are now at the point where we can build on it with more automation and smarts to make the design process even more intelligent. And with AI and with the overall smarts that we are becoming accustomed to from our technologies in general, we will expect them from our professional tools as well. Skema seems to be a great example of this “going beyond BIM” development in AEC.  

About the Author

Lachmi Khemlani is founder and editor of AECbytes. She has a Ph.D. in Architecture from UC Berkeley, specializing in intelligent building modeling, and consults and writes on AEC technology. She can be reached at


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