Cannot edit a building made with in Site Design 3d sketch with the Building Design tools

[trevor.clarkM88RA]

It appears that only "basic buildings" can be converted to the "Building Design" tab/tool set, is that correct? A mass made with the 3d sketch tools cannot? Is there a button I'm missing? With all the actual design tools limited to only the Building Design tab, is there no way to do design with anything but an extruded plan shape? Even the simplest prefab metal build has sloped roofs which don't seem to be modellable in a way that can be used with the facade and lighting tools. This seems like it should be possible, is there something obvious I'm not seeing?

[kevin_vong1 · Accepted solution]

Hello,

You are reading this correctly, and you are not missing a button. Right now, only Basic buildings and Line buildings can be converted into Forma Building Design's Detailed Buildings. 3D Sketch Buildings, including masses you build with the 3D Sketch tools, cannot currently be converted to Building Design. This is a stated limitation of the current workflow between the two apps, not something you can unlock with a hidden setting: https://help.autodeskforma.com/en/articles/14182447-workflow-between-forma-site-design-and-forma-bui...

On top of that, Building Design's own volume tools are currently limited to straight-edged, extruded footprints, and the only roof tool available there is Move facade/roof, which shifts a flat plane rather than creating a pitched or sloped roof. So even setting the conversion limitation aside, a true sloped roof like on your metal building isn't something Building Design's native tools support yet either: https://help.autodeskforma.com/en/articles/13905176-designing-buildings-volumes-in-forma-building-de...

What is possible today is shaping that geometry inside Site Design itself. A Basic building can be converted to 3D Sketch and edited with pitched roofs, tilted facades, and similar freeform geometry, and it still functions as a building with area metrics and floor plans. These two articles walk through that workflow:

https://help.autodeskforma.com/en/articles/7852917-converting-forma-site-design-buildings-to-3d-sket...
https://help.autodeskforma.com/en/articles/14176621-editing-facades-and-roofs-of-3d-sketch-buildings

If you need the facade automation and lighting/analysis tools that live specifically in Building Design, the extruded plan shape approach via an unconverted Basic building is the only supported path there today.

If this answered your question, please consider marking it as the solution. It helps others with the same limitation find the answer more easily.

Best,
Forma Design

[harrisonneil580]

One practical way to approach this is to separate the workflow into two stages: use Site Design for the geometry you actually need, then keep the Building Design workflow focused on the parts it currently supports.

For a building with a pitched or irregular roof, I’d avoid trying to force the 3D Sketch mass into Building Design. Instead, create the Basic building first if you need the Building Design tools, and use the Site Design/3D Sketch workflow for the more detailed roof and facade geometry.

If the main goal is facade studies or lighting analysis, it may also be worth keeping a simplified Building Design version alongside the more accurate Site Design model. That way you can work with the supported Building Design tools without losing the actual architectural geometry.

The limitation is frustrating, but this approach should avoid rebuilding the same model every time you need to switch between the two workflows.

[kevin_vong1]

Hi @harrisonneil580 

Thanks for your input. Yes this is a good comprimise until we roll out more features to address this. 

Best, 
Forma Design

[harrisonneil580]

I think the important distinction here is between a 3D Sketch mass and a Basic Building created through the Building Design workflow. If the Building Design tools only recognize the latter as an editable building object, then a mass created with 3D Sketch may not automatically gain access to those tools.

For the sloped-roof example, I wouldn't expect recreating the whole building as a simple extruded footprint to be a practical solution. A better workflow would be to check whether the roof geometry can first be represented through the supported building form/roof controls, rather than treating the 3D Sketch mass as something that can simply be converted.

I'd also test a very small case: create a basic rectangular building, apply the Building Design tools, then create the same footprint as a 3D Sketch mass and compare which commands become available. That should quickly confirm whether this is an intentional limitation or a missing conversion capability.

If 3D Sketch geometry genuinely cannot be promoted into the Building Design workflow, I agree that this is a significant limitation for anything beyond simple extruded buildings. Sloped roofs and irregular forms are common enough that having to rebuild the geometry just to access facade and lighting tools would be a frustrating workflow.

It would be useful if Autodesk could clarify whether 3D Sketch → editable Building Design object is supported or planned. That seems to be the key question here.