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

[Karen Walkerman]

The approach we take in EP3 (https://ep3.solutions), is similar to Chris's
description of creating "watertight" 2D CAD drawings. 2D floorplans are
created, and then walls are extruded up to intersect with flat or pitched
roofs.

If you already have clean CAD drawings, you can translate them to EP3
floors with one click.

In EP3, instead of grouping 3D surfaces by space or zone, we maintain the
2D floorplans, and have exterior walls, interior walls, and roof surfaces.
The major advantage is that changes to floorplans can be made in the 2D
floorplans at any phase of the project.  Adjacent zone geometry, walls, and
intersections with complex roof shapes happen automatically. This makes it
much easier to adapt and update building geometry as a project moves from
SD through to construction.

While EP3 is primarily uses EnergyPlus as a simulation engine, we can also
create eQuest geometry, constructions, schedules and internal loads.

Best,

Karen

On Thu, Sep 25, 2025, 22:51 Chris Yates via Bldg-sim <
bldg-sim at lists.onebuilding.org> wrote:

> 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,
> <https://www.google.com/maps/search/D-1%2F25,+Vasant+Vihar,+New+Delhi+110057?entry=gmail&source=g>
>  Vasant Vihar, New Delhi 110057
> <https://www.google.com/maps/search/D-1%2F25,+Vasant+Vihar,+New+Delhi+110057?entry=gmail&source=g>
>
>
>
> [m] +91 9899240140    [t]  +91 11 4056 8633
>
> gurneet at edsglobal.com | www.edsglobal.com
>
> Achieving water resilience with LEED Zero Water – setting a new standard
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