Energy model of a building with FreeCad

[paullee]

Indeed, just I have no idea what model file an energy analysis software needs. And would IFC already support such kind of usage so make it universal ?

[yorik]

just I have no idea what model file an energy analysis software needs

Basically GBXML.

All those edges may be 'disconnected', and maybe in the first place (before Topologic intervention), how to determine which side is inner or outer...

In IfcOpenShell there is apparently a tool that does just that (cannot find it back in https://twitter.com/aothms 's posts), that can determine "enclosed areas" from a bunch of lines

[paullee]

Basically GBXML.

Thanks for the pointer

Maybe a simple example can be used to show the possible workflow ? Anyone interested in going through the process and record it here?

Is the concept of 'CellComplex' (a bunch of solids representing each rooms with a common face against their connecting room), useful here ? I can contribute by showing the workflow for its creation, say :

1. 'Draw' the layout of a floor plan in a (Arch)Sketch, single-line.
2. Can use the already available Villa Savoye model or any simple layout as desirable.
3. Creating the 'CellComplex' for exporting - Topologic can read and analysis this as demonstrated by Dr. Wassim Jabi earlier.

Ping

[paullee]

There is a discussion at OSArch, it mention IfcRelSpaceBoundary.

Not much idea about the discussion OSArch Discussion , but screencapture seems great.

[ragohix769]

https://www.youtube.com/channel/UCIzy_X ... FqA/videos

Pity there is no known efforts from anyone to developping some WB or script or process to interface in some way Ladybug tools (and especially Honeybee) with our FreeCAD, so there are only video using... Sketchup

[lambda]

As others have noted already, the real problem is not writing an interface to ladybug tools or whatever engine. The problem is getting the data structures (objects) in FreeCAD to meaningfully store the inputs and results of such calculations.

Also, since this is mostly about relations between rooms via known faces, topological naming stability is a rather serious issue.

That said, it's possible to do many useful energy calculations with FreeCAD and minimal python glue. I think, this thread would benefit greatly, if you would explain a specific problem, you want to solve, instead of the tool, you want to use.

@paulee Yes, IFC4 has the basics. Getting FreeCAD to properly import, generate, export and validate the relevant IFC data structures including IfcSpace and IfcRelSpaceBoundary objects would be a huge step in the right direction. I looked into SpaceBoundaries in some detail about two years ago.

[paullee]

Thanks.

As others have noted already, the real problem is not writing an interface to ladybug tools or whatever engine. The problem is getting the data structures (objects) in FreeCAD to meaningfully store the inputs and results of such calculations.

Also, since this is mostly about relations between rooms via known faces, topological naming stability is a rather serious issue.

I have not much idea how all these works; maybe someone can do a minimal example and the community to work on and add featues?

'Toponaming problem' can be tackled separately.