Multithreading in Python

Hi everyone,

Today I was trying to apply multithreading to ghPython from what I learned of a video tutorial that I have just seen, but when I apply this script:

import ghpythonlib.parallel as ghp
import Rhino.Geometry.Point2d as Point2d

def ptsX(pts):
    return pts.X

ptX =, pts, True)

it’s giving me this error and I don’t know why

Runtime error (ArgumentTypeException): expected Func[object, object], got function

What is pts?

Seems to work here if:

pts = [Point2d(0, 0), Point2d(1, 1), Point2d(2, 2)]

Also tried with a collection of 3d points to x (list access):

Hi Nathan

Sorry my bad, pts is a points’ list that have passed through the “Set” component (to eliminate possible duplicate entries).

I tried your script and it works perfectly … but when i tried to adapt it to my needs I have failed miserably. So here is what I´m trying to do:

  1. Import 3D point list from a text file
  2. Extract their coordenates (X, Y, Z)
  3. Convert them to 2D point list.
  4. Apply what I have learnt from a video tutorial about multithreading.

So when I applied your code it worked, but when ever I try to reference pts (point 3D list) I fail miserably and I don’t understand why …

Tried running through a set but it didn’t change anything. I’d have to see how pts is being generated to suggest anything else.

Hi Nathan,

Thank you for replying and sorry if I was late, I think the I have just pinpointed the error.

See the first comment since that is what I intend to do next, : GhPython BooleanDifference Multi threading

Hi Nathan,

Here is a sample of the expected items in pts:

    {463578.31, 8.0621e+6, 335.614}
    {463570.355, 8.0621e+6, 334.853}
    {463558.771, 8.0621e+6, 334.569}
    {463546.948, 8.0621e+6, 333.58}
     . . . etc

All the problem that I had was that Grasshopper’s Parallel module needed a list to work.

So the new script is:

    import ghpythonlib.parallel as ghp
    import Rhino.Geometry.Point2d as Point2d

    ptslist = pts

    pts2D =, ptslist, True)

So @nathancoatney , if you known another way to improve my script I will gladly hear it.

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