[BlenderBIM] Concept building to BlenderBIM

D by dimitar on 21 Feb 2023, edited 21 Feb 2023 # +4 votes

Hi everyone.

I have been working on a new module for the Blender Architecture Masterclass Course , where the goal is to introduce users to various fairly easy-to-use strategies for using Blender for architectural design. The final model will be a residential tower on a podium. Here is a WIP of the model (still some rough parts)

Now I am thinking that further down, it may be nice to perhaps collaborate with someone and make this same model a BIM model. So before, finalising the model, I want to check about certain strategies and how well they can translate into BlenderBIM and/or Freecad, in particular with geometry nodes instances.

The organisation of this model is as follows:

Floors plans are imported from cad and drawn in Blender, and in this case each floor plate is the same. I hence model one floor plan, including the facade in a collection and then instance it with geometry nodes.

Facade consists of two objects - the solid and tha glazing, created with the Tissue addon, so they are real geometry.

Kitchens, lights, beds - all instanced with geometry nodes. I guess here is the biggest challenge. and I suspect, I may know the answer. How would one create a schedule for example of all light fixtures, kitchen lengths, etc? I imagine that within each geometry nodes tree, a separate output may be needed or some other way to "grab" the number of instances and output it somewhere else.

B by brunopostle on 21 Feb 2023 #

This is an issue with IFC itself, there is no defined mechanism for saying 'these floors are all identical', each storey has to exist in the IFC file in its entirety. ie. if you count the number of IfcLightFixture elements in the IFC file, this is the number of light fixtures in the building.

So your IFC file is going to contain a large amount of duplicated redundant information under all circumstances.

Now blenderbim does have an 'array' modifier that allows you to duplicate things in a way that allows them to be edited together later. I have no idea if this is suitable for arraying entire floors, or if it can be connected to geometry nodes in some kind of automatic way. Similarly there are now IFC sverchok nodes that can be used to generate/assign IFC elements, but don't know if these can be connected to your geometry nodes workflow.

@Moult it looks like the array modifier works by tagging each arrayed element with its position in the array, did you consider adding the elements to a special IfcGroup where the array information is stored? - this group would have the requirement that all nested elements have the same class and that each could be replaced interchangeably (though the GUID, Name, Description etc.. could be persistent). This mechanism would extend to duplicated elements that are not repeated in a regular grid, ie. @dimitar s kitchens would be duplicates, but may be oriented irregularly.

D by dimitar on 21 Feb 2023, edited 21 Feb 2023 #

@brunopostle said:

This is an issue with IFC itself, there is no defined mechanism for saying 'these floors are all identical', each storey has to exist in the IFC file in its entirety. ie. if you count the number of IfcLightFixture elements in the IFC file, this is the number of light fixtures in the building.

So your IFC file is going to contain a large amount of duplicated redundant information under all circumstances.

That's what I thought - there would need to be a concept design model that then gets "baked" without an easy way to utilise instances.

I wonder if attributes within geometry nodes (and elsewhere) can somehow be plugged into using BlenderBIM as IFC tags

Alternatively, what is the recommended concept design workflow for large buildings in BlenderBIM that can be somewhat comparable working with groups in Revit? Is it the BlenderBIM array modifier? Or with Sverchok?

T by theoryshaw on 21 Feb 2023, edited 21 Feb 2023 # +1 votes

Alternatively, what is the recommended concept design workflow for large buildings in BlenderBIM that can be somewhat comparable working with groups in Revit? Is it the BlenderBIM array modifier? Or with Sverchok?

This has been a long, on going shortcoming of the IFC schema--as i understand it.

This is the saga: https://github.com/IfcOpenShell/IfcOpenShell/issues/2283

I would love to see this functionality as well. Is quite crucial, for designing.

P by paullee on 21 Feb 2023 #

Can share the floor plan here? Had tried modeled some residential towers in FreeCAD and always curious how to take quantities from it :D