Python MAP Function

Scripting
,
1

Hi,

Can anyone please provide an example of using Python MAP function with a Rhino syntax command instead of a loop, tried and failed so need a little guidance.
Something simple like a “surfaceclosestpoint” select one surface and a list of existing 3d points that was what I was trying and return the list of the 3d closest points on the surface.

Regards
Roger

2

Hi @RogerD,

How about this?

#! python3
import rhinoscriptsyntax as rs

def __MyFunc(srf, point):
    uv = rs.SurfaceClosestPoint(srf, point)
    return rs.EvaluateSurface(srf, uv[0], uv[1])

def Test():
    srf = rs.GetObject("Select a surface", rs.filter.surface)
    if not srf:
        return

    points = rs.GetPoints(False, False, "First point", "Next point. Press Enter when done")
    if not points:
        return

    results = map(lambda x: __MyFunc(srf, x), points)
    for p in list(results):
        print(p)

if __name__ == '__main__':
    Test()

– Dale

1 Like
3

Hi Dale,

Thank you for this I have applied it to a few other functions and it seems quicker than a loop when dealing with lots of points maybe a couple of examples on the help files could assist other users.

Regards

Roger

4

Hi Dale,

I have been playing with the map function and find it quite useful however I have come across a problem, using BrepClosestPoint if I try to get both arrCP[0] and arrCP[3] at the same time I get the output like

arrCP = (<Rhino.Geometry.Point3d object at 0x00000226F371E640>, <Rhino.Geometry.Vector3d object at 0x00000226F371E6C0>)

however if I get them one at a time using two functions one for the arrCP[0] and one for arrCP[3]
I get what I expect a 3d point -115.73961229639679,-45.38981434783973,0 and a vector 0,-0,-1
why does the output change if I get both together which is what I want so the vector is relative to the correct point if I add them to the workspace.

Roger

#! python3

results = []
resultsa = []

import rhinoscriptsyntax as rs

def __MyFunc(srf, point):
    arrCP = rs.BrepClosestPoint(srf, point)
    #uv = rs.SurfaceClosestPoint(srf, point)
    return (arrCP[0], arrCP[3])
    #return rs.EvaluateSurface(srf, uv[0], uv[1])

#def __MyFunc1(srf, point):
    #arrCP = rs.BrepClosestPoint(srf, point)
    #uv = rs.SurfaceClosestPoint(srf, point)
    #return arrCP[3]

def Test():
    srf = rs.GetObject("Select a surface", rs.filter.surface)
    if not srf:
        return

    points = rs.GetObjects("Pick some points", rs.filter.point)
    if not points:
        return

    results = map(lambda x: __MyFunc(srf, x), points)

    #resultsb = map(lambda x: __MyFunc1(srf, x), points)

    for p in results:
        print("arrCP = ", str(p))
5

What you print out now is a tuple of a point and vector. You still get what you want, it is just not the same string representation. with the function you have now in use you can print("arrCP = ", str(p[0]), str(p[1])), which will give the same stringified version of the tuple elements.

What you are seeing is the repr() result of the elements in the tuple.

6

Thank you Nathan great explanation

7

Hi Nathan and Dale,

I am still playing with the map function and I have question once I get my results from the map of my function how would I add the points generated to the workspace using another map and not having to go through a loop “for (p) in results”.
I have attached a test file if you select a surface and some points it should generate two points and a curve between them representing the closest point and the surface normal from that point.

Roger
test1.3dm (398.4 KB)

#! python3
import rhinoscriptsyntax as rs


def __MyFunc(srf, point):
    uv = rs.SurfaceClosestPoint(srf, point)
    return [rs.EvaluateSurface(srf,uv[0],uv[1]), rs.SurfaceNormal(srf, uv)]


def Test():
    srf = rs.GetObject("Select a surface", rs.filter.surface)
    if not srf:
        return

    points = rs.GetObjects("Pick some points", rs.filter.point)

    if not points:
        return

    results = map(lambda x: __MyFunc(srf, x), points)



    if results:
        
        for p in list(results):
            
            rs.AddPoints([(p[0]), (p[0])+(p[1])])
            rs.AddLine((p[0]), (p[0])+(p[1]))


if __name__ == '__main__':
    Test()
8

You can always do another map using the map object in results. You could for instance use it to gather the GUIDs of the points and lines you add:

#! python3
import rhinoscriptsyntax as rs


def __MyFunc(srf, point):
    uv = rs.SurfaceClosestPoint(srf, point)
    return [rs.EvaluateSurface(srf,uv[0],uv[1]), rs.SurfaceNormal(srf, uv)]


def __RealizeObjects(p):
    point_guids = rs.AddPoints([(p[0]), (p[0])+(p[1])])
    line_guid = rs.AddLine((p[0]), (p[0])+(p[1]))
    return (point_guids, line_guid)


def Test():
    srf = rs.GetObject("Select a surface", rs.filter.surface)
    if not srf:
        return

    points = rs.GetObjects("Pick some points", rs.filter.point)

    if not points:
        return

    results = map(lambda x: __MyFunc(srf, x), points)
    new_guids = map(lambda p: __RealizeObjects(p), results)
    print(list(new_guids))

if __name__ == '__main__':
    Test()
9

thank you Nathan I will give it a go

10

Hi Nathan,

Why does this not work when trying to use BrepClosestPoint but the concept work with SurfaceClosestPoint. I cannot get the second map function to add the points and curves, so much to learn and so little time to do it.

Roger

#! python3


points = []

results = []



import rhinoscriptsyntax as rs

def __MyFunc(srf, point):
    arrCP = rs.BrepClosestPoint(srf, point)
    return [arrCP[0],arrCP[3]]


def __RealizeObjects(p):
    point_guids = rs.AddPoints([(p[0]), (p[0])+(p[1])])
    line_guid = rs.AddLine((p[0]), (p[0])+(p[1]))
    return (point_guids,line_guid)


def Test():
    srf = rs.GetObject("Select a surface", rs.filter.surface)
    if not srf:
        return

    points = rs.GetObjects("Pick some points", rs.filter.point)
    
    if not points:
        return

      
    results = list(map(lambda x: __MyFunc(srf, x), points))

    new_guids = map(lambda p: __RealizeObjects(p), results)


        
    #if results:
        
        #for p in list(results):
            #rs.AddPoints([(p[0]), (p[0])+(p[1])])
            #rs.AddLine((p[0]), (p[0])+(p[1]))

            #print((p[0]))
            #print((p[1]))

    #new_guids = map(lambda p: __RealizeObjects(p), results)

    #if results:
        
        #for p in list(results):
            #rs.AddPoints([(p[0]), (p[0])+(p[1])])
            #rs.AddLine((p[0]), (p[0])+(p[1]))

            #print((p[0]))
            #print("pt = ",pt)

        #for p in points:
            #print(p)

if __name__ == '__main__':
    Test()
11

Works just fine for me:

#! python3
import rhinoscriptsyntax as rs


def __MyFunc(srf, point):
    res = rs.BrepClosestPoint(srf, point)
    return (res[0], res[3])


def __RealizeObjects(p):
    point_guids = rs.AddPoints([(p[0]), (p[0])+(p[1])])
    line_guid = rs.AddLine((p[0]), (p[0])+(p[1]))
    return (point_guids, line_guid)


def Test():
    srf = rs.GetObject("Select a surface", rs.filter.surface | rs.filter.polysurface)
    if not srf:
        return

    points = rs.GetObjects("Pick some points", rs.filter.point)
    if not points:
        return

    results = map(lambda x: __MyFunc(srf, x), points)
    new_guids = map(lambda p: __RealizeObjects(p), results)


if __name__ == '__main__':
    Test()
12

Hi Nathan,

Didn’t work for me and I couldn’t work out why so back to the drawing board, thanks again.

13

This is the Rhino version I am using

Version 8 SR14
(8.14.24337.13001, 2024-12-02)
Commercial
SN: 6-1802-0101-1-39636-34008
Roger Davies

the script runs with no error but does not add the points and curves to the workspace if you try it with the simple model I sent you maybe you will get the same as me.