Slow to find all objects inside or near an object

[Amoki]

I'm trying to fetch all objects "near" an object.
For example, all objects inside an IfcSpace and walls on its sides, or find spaces and slabs touching a wall.

I'm using geom.tree() and the select() method but if I add an extend parameter to find close objects, the process time is multiplied (from milliseconds to seconds per object).

if ifc_object.is_a("IfcProduct"):
   nearby_instances = [
       i.GlobalId for i in ifcwrap_bvh.select(ifc_object, extend=1.1)
   ]

Is this the right way to do it or am I in the wrong direction?

[aothms]

I guess it depends on the model. Extending by 1.1m I guess could make the number of objects to consider go up exponentially. If ifc_object is complex (which means computing distances from it takes some time). Regardless of that I think "seconds per object" is definitely on the slow side. Would be good to have a model + guid so that I can run it in the profiler.

[Amoki]

import ifcopenshell
from ifcopenshell import geom
import multiprocessing

from ifcopenshell.util.selector import Selector


selector = Selector()

ifc_file = ifcopenshell.open("MarcAntoinePetit.ifc")


# Construct BVH with ifcopenshell.geom()
bvh_tree = geom.tree()
settings = geom.settings()
exclude_elements = selector.parse(ifc_file, ".IfcSpace | .IfcOpeningElement")

iterator = geom.iterator(
    settings,
    ifc_file,
    multiprocessing.cpu_count(),
    exclude=exclude_elements,
)

if iterator.initialize():
    while True:
        bvh_tree.add_element(iterator.get_native())
        if not iterator.next():
            break

# Retrieving nearby Ifc instances
nearby_instances = {}
for ifc_product in ifc_file.by_type("IfcProduct"):
    nearby_instances[ifc_product.GlobalId] = [
        i.GlobalId for i in bvh_tree.select(ifc_product)  # , extend=0.1)
    ]

MarcAntoinePetit.zip

Without extend: 164 sec (95% of the time is on bvh_tree.select(ifc_product))
With extend=0.1: I gave up after 1 hour

With only the first 500 products:

nearby_instances = {}
for ifc_product in ifc_file.by_type("IfcProduct"):
    if len(nearby_instances) > 500:
        break
    nearby_instances[ifc_product.GlobalId] = [
        i.GlobalId for i in bvh_tree.select(ifc_product)
    ]

Without extend: 29 sec
With extend=0.1: 1434 sec

Some objects are way slower than others.

1T2hYTZj1EsBZaf4hQmbLI (IfcWallStandardCase)
3RLTfSMBXE_BWgA7Wbvfa1 (IfcSlab)
0dWoULYUH3zPg8qJpTnRTP (IfcWallStandardCase)
0dWoULYUH3zPg8qJtTnRTP (IfcWallStandardCase)
3SsBdsN_n49RzlgartcT0T (IfcBuildingElementProxy)

take more than 60 seconds each with extend

The slowest is the IfcBuildingElementProxy (it's always them) 3SsBdsN_n49RzlgartcT0T
It takes 0.005 sec without extend and 90.207 sec with extend.

[Moult]

This is now fixed with the new clash detection features. The clearance clash is also much, much faster.