GHPython: PolyCurve is not iterable

[MishaBro]

Hi friends!

I am learning how to write code in GHPython.
I am trying to iterate over a data tree collecting curves, find periodic curves, close them within the tree, return the tree with all closed curves.

I am getting an error: PolyCurve is not iterable

The input is Tree Access, No Type Hint (tried curve as well).

What am I doing wrong?

Thank you!

Rhino 6, Windows 10.ghpython_err.gh (493.2 KB)

[efestwin (Max Eschenbach)]

Printing out crv after the conversion to list shows that it’s just one PolyCurve in a list. I don’t know why, possibly a bug in treehelpers @piac ?

As a workaround you could loop directly over the tree without converting it, like so:

import rhinoscriptsyntax as rs

a = []

for i, branch in enumerate(crv.Branches):

    for j, item in enumerate(branch):
        
        if rs.IsCurveClosed(item):
            bool = "closed"
            a.append(item)
        else:
            bool = "periodic"
            pts = list(rs.CurveEditPoints(item))
            pts.append(pts[0])
            a.append(rs.AddInterpCurve(pts,1,2))

Note, that you have to set typehint to ghdoc if you want to use rhinoscriptsyntax!

Hope that helps

[kev.r (Kevin)]

@efestwin

Printing out crv after the conversion to list shows that it’s just one PolyCurve in a list. I don’t know why, possibly a bug in treehelpers

This is normal when using treehelpers with simplified trees (no common root branch).

See explanation here:

Treehelpers with simplify

Hi Lukas, this is expected and is designed to work this way. Let’s see from the beginning: a “simplified tree” is not a normal tree anymore, it is a “forest”. There is no base branch (“trunk”?) in common anymore, so paths represent distinct trees. Grasshopper components alone, in fact, usually do not create this type of forests. To work with this type of “forest”, a base list in Python would always have to be created, to support these distinct routes. This is however unwelcome, because it woul…

And here:
https://gist.github.com/piac/ef91ac83cb5ee92a1294#gistcomment-3763417

Original code works with these changes (and changing input type hint to ghdoc as @efestwin pointed out):

import ghpythonlib.treehelpers as th
import rhinoscriptsyntax as rs

crv = th.tree_to_list(crv, lambda crv: crv)

a = []

for i,branch in enumerate(crv):
    
    for j,item in enumerate(branch):
        if rs.IsCurveClosed(item):
            bool = "closed"
            a.append(item)
        else:
            bool = "periodic"
            pts = list(rs.CurveEditPoints(item))
            pts.append(pts[0])
            a.append(rs.AddInterpCurve(pts,1,2))

ghpython_err_210912a.gh (493.1 KB)

-Kevin

[efestwin (Max Eschenbach)]

@kev.r

This is normal when using treehelpers with simplified trees (no common root branch).

Aaah yeah, this makes sense and I completely forgot it since I prefer working directly with trees.

Thank you for the refresher! Very much appreciated