Best Way to Test if 2 points are coincident?

[dirktheeng]

So, I need to test if 2 sketchPoints lay on top of eachother in a sketch.  Say the sketch points are sp1 and sp2

First, I make a point 3d object

p1 = sp1.geometry

p2 = sp2.geometry

Then compare the cooridnates

is |p1.x - p2.x| < smallNumber and |p1.y - p2.y| < smallNumber

The question is how small does small number have to be?  Or is there an entirely better way of doing this?

[KrisKaplan · Accepted solution]

The easiest way to do this would be to use Point3D's isEqualTo method.

equal = sp1.geometry.isEqualTo(sp2.geometry)

This will use the modeler's default system tolerance (which is 1e-6).  This is the tolerance that we would use to test for any general point equality.  If you want to use some other tolerance, you can use the distanceTo method.

equal = sp1.geometry.distanceTo(sp2.geometry) <= myTol

Kris

[Anonymous]

I try the following coding ,but this is error

import adsk.core, adsk.fusion, adsk.cam, traceback

def run(context):
    ui = None
    try:
        app = adsk.core.Application.get()
        ui  = app.userInterface
        product = app.activeProduct
        design = adsk.fusion.Design.cast(product)

        root = design.rootComponent
        sketches = root.sketches
        sketch = sketches.add(root.xYConstructionPlane)
        sketchPoints = sketch.sketchPoints
        a1 = adsk.core.Point3D.create(1, 1, 1)
        a2 = adsk.core.Point3D.create(0, 3, 0)
        sketchPoint1 = sketchPoints.add(a1)
        sketchPoint2 = sketchPoints.add(a2)
        sp1 = sketchPoint1.geometry
        sp2 = sketchPoint2.geometry
        equal = sp1.geometry.isEqualTo(sp2.geometry)
        print (equal)
        
    except:
        if ui:
            ui.messageBox('Failed:\n{}'.format(traceback.format_exc()))

could you tell me why, and how to improve it 

[BrianEkins]

The reason for the failure is that you're getting the Point3D object from the sketch point using the geometry property an assigning it so sp1 and sp2 and then in the following line you're trying to call the geometry property on sp1 and sp2 but they're Point3D objects and don't have a geometry property.  Just change this line:

equal = sp1.geometry.isEqualTo(sp2.geometry)

to this:

equal = sp1.isEqualTo(sp2)