Find nearby objects with Python

Its_Alive · October 22

A quick example on using cad-pyrx kdtree’s to do a radius search. This is a drawing of a sprinkler system, where the parts are inserted as blocks. The goal is to find all the components within a given radius and list them

from pyrx import Db, Ed, Ge, Ap, Rx, Gs


# create a new command in BricsCAD
@Ap.Command()
def doit():
    try:
        # get modelspace
        db = Db.curDb()
        model = db.modelSpace()

        # get all the block BlockReference
        refs = [Db.BlockReference(id) for id in model.objectIds(Db.BlockReference.desc())]

        # list and map the positions
        allmid = []
        pnt_ref_map = {}
        for ref in refs:
            mid = ref.getGeomExtents().midPoint()
            pnt_ref_map[mid] = ref
            allmid.append(mid)

        # create a kdtree
        tree = Ge.Point3dTree(allmid)

        # search sphere 6"
        rad = 6

        # positions we will search from
        targets = [ref.position() for ref in refs if ref.getBlockName() == "SPK-51-112-1-160-PW"]

        for pnt in targets:
            indexs, dists = tree.radiusSearch(pnt, rad * rad)
            print("\ngroup")
            for idx, dist in zip(indexs, dists):
                if dist == 0:
                    continue
                if allmid[idx] in pnt_ref_map:
                    pnt_ref_map[allmid[idx]].highlight()
                    print(pnt_ref_map[allmid[idx]].getBlockName())

    except Exception as err:
        print(err)

Its_Alive · October 22

Here’s another example, I want to find all the computers located near a phone

import traceback
from pyrx import Ap, Ax, Db, Ed, Ge, Gi, command

# radiusSearch
@command
def doit():
    db = Db.curDb()
    phones, computers = getBlocks(db)
    result = []

    # create the tree of phone locations
    phonePoints = Ge.Point3dArray()
    for phone in phones:
        phonePoints.append(phone[1])
    phoneTree = Ge.Point3dTree(phonePoints)

    # search for nerby phones
    for computer in computers:
        idxs, _ = phoneTree.radiusSearch(computer[1], 50 * 50)# sqrd
        if len(idxs) == 0:
            print("no phone")
            continue
        for idx in idxs:
            result.append((computer, phones[idx]))

    for cpu, phn in result:
        Ed.Core.grDraw(cpu[1], phn[1], 2, 0)


# helper, store the id and position
def getBlocks(db: Db.Database):
    phones = []
    computers = []
    model = Db.BlockTableRecord(db.modelSpaceId())
    refs = [Db.BlockReference(id) for id in model.objectIds(Db.BlockReference.desc())]
    for ref in refs:
        if ref.getBlockName() == "COMPUTER":
            computers.append((ref.objectId(), ref.position()))
        elif ref.getBlockName() == "FNPHONE":
            phones.append((ref.objectId(), ref.position()))
    return phones, computers

ALANH · October 22

Could not resist, did a "where is" for staff similar method to yours, but added their staff photo to the desk. Used the phone number, a phone block, as the name of the image. Also added a Grid so found me at 5th floor "A1", yes was multiple floors.

For non Pyhton, use SSget "WP" PTS, just make a list of points based on a centre point and a radius. Very easy using (Polar cenpt rad ang). Just keep incrementing ang with small increments. Say (setq inc (/ (* 2 pi) 20)

Its_Alive · October 22

Sure, you could do this with lisp, the 3D (r3) search might be hard, also performance might become an issue at scale. I used nanoflann, if your interested in the performance characteristics https://github.com/jlblancoc/nanoflann

My source is here https://github.com/CEXT-Dan/PyRx/blob/main/PyRxCore/PyGePoint3dTree.cpp

Find nearby objects with Python

Comments