bug in rs.PlaneCurveIntersection

[geef]

Hi Steve,

the rs.PlaneCurveIntersection() does not work.
I tried this script from the help

Python Code:

import rhinoscriptsyntax as rs
 
 
 
curve = rs.GetObject("Select curve", rs.filter.curve)
 
if curve:
 
    plane = rs.WorldXYPlane()
 
    intersections = rs.PlaneCurveIntersection(plane, curve)
 
    if intersections:
 
        for intersection in intersections:
 
            rs.AddPoint(intersection[1])

but it constantly throws an error.
See image attached.

Could you please have a look a it!

Thanks!

[Mitch]

Yes, there is a bug in this function. It will fail if no intersection is found.

Python Code:

def PlaneCurveIntersection(plane, curve, tolerance=None):
    "Intersect an infinite plane and a curve object"
    plane = rhutil.coerceplane(plane, True)
    curve = rhutil.coercecurve(curve, True)
    if tolerance is None: tolerance = scriptcontext.doc.ModelAbsoluteTolerance
    intersections = Rhino.Geometry.Intersect.Intersection.CurvePlane(curve, plane, tolerance)
    #<-- the rc=[] line below should actually be here
    if intersections:
        rc = []  # rc is defined only if there are intersections
        for intersection in intersections:
            a = 1
            if intersection.IsOverlap: a = 2
            b = intersection.PointA
            c = intersection.PointA2
            d = intersection.PointB
            e = intersection.PointB2
            f = intersection.ParameterA
            g = intersection.ParameterB
            h = intersection.OverlapA[0]
            i = intersection.OverlapA[1]
            j = intersection.OverlapB[0]
            k = intersection.OverlapB[1]
            rc.append( (a,b,c,d,e,f,g,h,i,j,k) )
    return rc  # will fail if intersections is None
 

--Mitch

[geef]

Hi Mitch,

thanks for your reply and your help!
I also found that error and moved the rc = [] two lines up.
But for me that didn't help ?

[Mitch]

It should work. Make sure you got the indent right and most importantly - make sure all of the Rhino instances are closed BEFORE making the modifications to plane.py...

It works here.

--Mitch

[geef]

Hi Mitch,

ok got it.
I was trying to modify the plane.py directly via the script editor.
That didn't work.
Now it's fne....

Thanks again!

[Steve Baer]

My fix for this is almost the same as Mitch's except I indented return rc so it is only returned if there are intersections. This way if no intersections were found, then None is returned (based on another thread where Mitch asked for this type of functionality.) If a function ends and doesn't explicitly return something, then None is returned.

https://github.com/mcneel/rhinopytho...t/plane.py#L77

-Steve