Grasshopper File and Geometry Import Script

gistfile1.py

# Original code by bengolder https://gist.github.com/bengolder/1019295
# Modified by gperonato https://gist.github.com/gperonato/

#Inputs: FilePath (String) and DoImport (Boolean)
#Outputs: Geometry (Tree of geometry) and LayerList (List of strings)


import Rhino


# for accesssing GH classes
import clr
clr.AddReference("Grasshopper")
from Grasshopper.Kernel.Data import GH_Path
from Grasshopper import DataTree


# read geometry and layer names out of 3dm files
if DoImport and FilePath:
    
    Geometry = DataTree[Rhino.Geometry.GeometryBase]() # make a DataTree
    
    
    model = Rhino.FileIO.File3dm.Read(FilePath)
    Layers = model.Layers
    LayerList = []
    for layer in Layers:
        LayerList.append(str(layer))
    for i, layer in enumerate(LayerList):
        path = GH_Path(i)
        geometry = []
        objs = model.Objects.FindByLayer(layer)
        for obj in objs:
            geom = obj.Geometry
            geom.EnsurePrivateCopy()
            geometry.append(geom)
        Geometry.AddRange(geometry, path)
        # models can take up a considerable amount of
        # memory that we don't need, so get rid of it
        # after copying the geometry we want out of it
    model.Dispose()