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"site limit"-how to drew the exact boundary

Message 1 of 4
415 Views, 3 Replies

"site limit"-how to drew the exact boundary

Hi, there is an issue related to the "site limit" function. The percentage result in the "area metrics" is dependent on the site limit area. However, in some countries, there is a lack of land parcel data similar to Regrid in the USA. Therefore, I thought about using the Revit plugin to address this. I exported the proposal to Revit and drew the exact boundary using map overlay. Then, I updated the proposal and attempted to align the site area with the imported Revit model, but I couldn't find a snap function to capture the boundary of the floor in the imported model. Is there a better suggestion or alternative method you can recommend?

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Message 2 of 4
in reply to: averylin


I am really impressed with the way you try to find ways around the problem by looking at alternative workflows! Drawing the site limit in Revit, and then use the Revit plugin to import this site limit to Forma, does sound like a workflow we should support. 


But as you discovered, we have some missing functionality to make this work properly as the snapping in Forma is not yet supporting tracing edges from these geometries. Two alternative workarounds you may want to try:

1. When you import the site limit from Revit, with the Revit plugin, you should be able to trace the site limit in 3D Sketch. After you have traced the geometry in 3D Sketch, you should be able to re-trace it with the "site limit tool" in Design Mode

2. After drawn the site limit in Revit, you could export this geometry in DXF in the correct coordinate system. When you import this DXF file, you should be able to trace it directly in Design Mode with the "site limit tool"


Of the two alternatives mentioned above, I would recommend alternative 2.


As you see, we do lack some functionality to support the workflow you mentioned in a good way and I will bring your feedback to the product teams. 


Question: Out of curiosity, what is the reason you are not able to dra the site limit directly in Forma? Is it because we do not yet support importing an image which you would like to trace?




Message 3 of 4
in reply to: arne.bjelland

Hi Arne,
Thank you for your reply. The reason I am hesitant to draw the site limits directly in Forma is the lack of land parcel data in my location. It is currently not possible to accurately define the site boundary using available resources like OSM or any other available resources from order data. (However, please correct me if I am mistaken). Therefore, I assume that discussing the project with the owner based on the percentage in the area metric column would require the site area number to match the existing land parcel data. Otherwise, there may be potential arguments or objections.

Upon reconsidering your explanation, I realized that my confusion stemmed from a misunderstanding of what the ifc format supports. I mistakenly believed that I could see the 2D vector I draw within the same ifc file. However, as you clarified, the 2D vector should be exported as a DXF file, and the site limit tool can successfully trace the boundary from the DXF file. Unfortunately, my workflow is limited to the IFC format, which means there is no need for a snap-to function for the mesh model.

Message 4 of 4
in reply to: averylin

Hi! We should defiantly improve the snapping so it works in more use cases. Just when we will have time to prioritise this  improvement, is a little bit unclear.


Just some follow-up questions:

  • You mentioned your workflow is limited to IFC. Does that mean the option of exporting to a DXF in Revit is not as an option?
  • When you draw the site-limits in Revit you mentioned that yo drew the exact boundary using map overlay. Does that mean you have imported an image to Revit which you trace?

Just asking since I am curious:)


Have a nice day!


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