How to find the closest point on a solid/face to another point in 3d space

[bradphelan]

I have some code here that creates a random solid.

import cadquery as cq
from math import sin, cos, pi
from numpy import linspace

SEGMENTS = 48

def sinusoidal_ring(rad=25, segments=SEGMENTS):
    outline = []
    for i in range(segments):
        angle = i * 2 * pi / segments
        x = rad * (cos(angle) + i/segments)
        y = rad * sin(angle)
        z = 2 * rad * (sin(angle) / 5 + i / segments)
        outline.append((x, y, z))
    return outline

def triangle(base=15, ratio=2):
    return [(-base/2, 0), (base/2, 0), (0, base*ratio)]

def extrude_example():
    shape = triangle()
    path = sinusoidal_ring(rad=50)
    solid = cq.Workplane("YZ").polyline(shape).close().sweep(cq.Workplane("XY").spline(path, includeCurrent=True))

    # Project all points in a grid onto the shape and display
    for x in linspace(-10,10,10, endpoint=True):
        for y in linspace(-10, 10,10, endpoint=True):
            for z in linspace(-10, 10, 1, endpoint=True):
                
                point = (x, y, z)
                # find the closest point on any face of 'solid'
        
                
    show_object(solid)


extrude_example()

What I'd like to be able to do is given some random point in space P(x,y,z) find the closest point on solid S(x,y,z). Is this possible through the CQ api?

[bradphelan]

I've come up with a working solution that involves calling into the OCP library

import cadquery as cq
from math import sin, cos, pi
from numpy import linspace
from OCP.BRepExtrema import BRepExtrema_DistShapeShape


SEGMENTS = 48

def sinusoidal_ring(rad=25, segments=SEGMENTS):
    outline = []
    for i in range(segments):
        angle = i * 2 * pi / segments
        x = rad * (cos(angle) + i/segments)
        y = rad * sin(angle)
        z = 2 * rad * (sin(angle) / 5 + i / segments)
        outline.append((x, y, z))
    return outline

def triangle(base=15, ratio=2):
    return [(-base/2, 0), (base/2, 0), (0, base*ratio)]

def distance(self, other: "Shape") -> float:
    return BRepExtrema_DistShapeShape(self.wrapped, other.wrapped)





def extrude_example():
    shape = triangle()
    path = sinusoidal_ring(rad=50)
    solid = cq.Workplane("YZ").polyline(shape).close().sweep(cq.Workplane("XY").spline(path, includeCurrent=True))

    # Project all points in a grid onto the shape and display
    for x in linspace(-100,100,3, endpoint=True):
        for y in linspace(-100, 100,3, endpoint=True):
            for z in linspace(-100, 100, 3, endpoint=True):
                
                point = cq.Vertex.makeVertex(x, y, z)
                # Find the closest point on any face of 'solid'
                closest_point = distance(point, solid.val())
                closest_point.Perform()
                log(closest_point.PointOnShape1(1))
                log(closest_point.PointOnShape2(1))

                target = closest_point.PointOnShape2(1)
                target_vertex = cq.Vertex.makeVertex(target.X(), target.Y(), target.Z())
                show_object(target_vertex)
                
                e =cq.Edge.makeLine((x,y,z), (target.X(), target.Y(), target.Z()))
                show_object(e)
            
                
    show_object(solid)


extrude_example()

Any suggestions on how to make the code better would be appreciated. It was hacked together trying random things.