[Bldg-sim] Streamlining CAD-to-Building Simulation Workflows

[chris.malcolm.yates at gmail.com]

Hi Gurneet,

 

There are many formats and geometry paradigms (E+ has several ways of defining geometry). Some paradigms are based on simple collections of 3d polylines, whilst others are a bit more “parametric” and therefore predicated on some limitations (such as a single planar nGon defining the floor).

 

IES

Commercially, I can only speak of how I hack geometry into my tool of choice – IES VE. I’ve not found gbXML or IFC import very reliable to import into IES. However, there’s a function called constructDXF that is very good at extruding 2D cad plans into a 3d model. The cad plans have to be super-clean, but I don’t mind this because I’m very happy working in CAD. You need to create a stick drawing presenting watertight zones. Each zone has a line of Dtext in the middle representing the zone name. It’s a bit archaic and it’s generally not what they teach you on the training course! I think constructDXF has been part of the software for almost 30 years!

 

I believe the underlying geometry paradigm is 3d polylines. A “gem” (geometry) file can be exported out of IES in ascii text format. The format of this is definitely 3d polys.

 

IDA ICE

I also have some experience with IDA ICE. This tends to do a fairly decent job of importing IFC files, as long as the zones are valid (good luck with your architect). The zone definition appears to be more on the “parametric” side with IDA – a typical zone is prismatic but features such as a clipped roof can be applied. Max Tillberg at Equa has worked on a number of workflows to get geometry into IDA apart from using IFC. From what I understand, he’s had a degree of success using Rhino, Revit, Speckle, and even the open-source tool, Blender.

 

I hope that this helps.

 

Kind regards

 

Chris 

 

From: Bldg-sim <bldg-sim-bounces at lists.onebuilding.org> On Behalf Of Gurneet Singh via Bldg-sim
Sent: 25 September 2025 10:15
To: bldg-sim <bldg-sim at lists.onebuilding.org>
Subject: [Bldg-sim] Streamlining CAD-to-Building Simulation Workflows

 

Hi all,

We’ve been exploring ways to reduce manual effort in transferring geometry from CAD into building simulation formats like eQuest, gbXML, and others. In our recent work, we developed a plugin that facilitates this process by converting CAD lines directly into multiple simulation-ready formats (eQuest, GBXML, HAP, Rhino), aiming to save time and minimize errors.

I’d be very interested in feedback from this group on workflow improvements or challenges you’ve encountered when moving from CAD to simulation formats—especially regarding geometry accuracy and interoperability.

Best regards,

Gurneet Singh

Director

 

Environmental Design Solutions Pvt. Ltd.

D-1/25, Vasant Vihar, New Delhi 110057

 

[m] +91 9899240140    [t]  +91 11 4056 8633

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