ebrahimraeyat / freecad-blenderbim

A FreeCAD implementation of BlenderBIM (provisory name, might change!)

BlenderBIM addon for FreeCAD

This is a preliminary stub to integrate BlenderBIM into FreeCAD. The final goal is to offer in FreeCAD the same level of functionality found in BlenderBIM, mainly the native handling of IFC files, which means the data manipulation in FreeCAD is affecting directly the IFC model.

Roadmap

1. Get a working concept up

• Write an importer that allows an initial import of an IFC file into FreeCAD
• Write a custom parametric FreeCAD object that represents an IFC document in the FreeCAD tree
• Do an initial geometry import
• Write a custom parametric FreeCAD object that represents in IFC product in the FreeCAD tree
• Reveal the document structure in the FreeCAD tree
• Add a shape caching system
• Allow an object shape to be built automatically from its children
• Allow to expand a document (reveal its children)

2. Allow basic editing

• Allow different import strategies (full model, only building structure...)
• Allow different storage strategies (the shape is transient or not, coin representation only, etc..)
• Allow to change a parameter of an object
• Write a hook system that allows FreeCAD to save the IFC document
• Test what happens when opening a bb file in vanilla FreeCAD

Installation & Usage

Auto install

The advantage of this approach is the ability to update FreeCAD-BlenderBIM workbench via the addon manager.

• Open the Addon Manager preferences via Edit → Preferences → Addon Manager → Custom Repositories
• Add https://github.com/yorikvanhavre/FreeCAD-BlenderBIM to Custom Repositories list. In the Branch section indicate the main branch. Press OK.
• Start the Tools → Addon Manager which will automatically find FreeCAD-BlenderBIM addon in the workbench list.
• Install FreeCAD-BlenderBIM addon
• Restart FreeCAD
  Result: FreeCAD-BlenderBIM IFC importer should be available in open/insert file dialogs

Manual install

• Navigate to your FreeCAD Mods folder (~/.local/share/FreeCAD/Mods)
• Clone this repo there: git clone https://github.com/yorikvanhavre/FreeCAD-BlenderBIM.git
• Restart FreeCAD
  Result: FreeCAD-BlenderBIM IFC importer should be available in open/insert file dialogs

To test

• Run FreeCAD
• File → Open or File → Insert, select an IFC file
• Select the BlenderBIM importer (bb_import)
• A FreeCAD document is created
• An object is created representing the IFC root document + project

Notes

Documentation

• IfcOpenShell github
• IfcOpenShell docs
• BlenderBIM docs
• IfcOpenShell matrix structire
• IfcOpenShell to FreeCAD matrix conversin

Code examples

Initial import + getting the main file structure

import ifcopenshell
f = ifcopenshell.open("IfcOpenHouse.ifc")
p = f.by_type("IfcProject")[0]
# get descendents (site, building, and everything inside)
d = ifcopenshell.util.element.get_decomposition(p)

Using the geometry iterator

import multicore
settings = ifcopenshell.geom.settings()
settings.set(settings.DISABLE_TRIANGULATION, True)
settings.set(settings.USE_BREP_DATA,True)
settings.set(settings.SEW_SHELLS,True)
settings.set(settings.USE_WORLD_COORDS,True)
settings.set(settings.APPLY_LAYERSETS,True)
shapes = []
cores = multiprocessing.cpu_count()-2
iterator = ifcopenshell.geom.iterator(settings, ifcfile, cores, include=entitieslist)
iterator.initialize()
while True:
    item = iterator.get()
    if item:
        ifcproduct = ifcfile.by_id(item.guid)
        brep = item.geometry.brep_data
        shape = Part.Shape()
        shape.importBrepFromString(brep, False)
        shape.scale(1000.0) # IfcOpenShell outputs in meters
        shapes.append(shape)
    if not iterator.next():
        break
compound = Part.makeCompound(shapes)

schependomlaan.ifc of 47Mb imports in 23s