How to access individual objects in a Compound object?

[huskier]

We want to access individual letter in the text3D Compound, and we've found there is a function called siblings(self, shape: "Shape", kind: Shapes, level: int = 1). We wonder how to call the siblings function properly??//

import cadquery as cq
from cadquery.vis import show

text_string = "Hello, CadQuery!"
font = "Arial"
size = 10  # in millimeters
text3D = cq.Workplane("XZ").text(text_string, combine = True, font = font, fontsize = size, distance = 2).val()

[lorenzncode]

access individual letter in the text3D Compound

You can access individual solid letters with iteration or unpacking.:

letter_o = [*text3D.val()][4]

or with selectors:

letter_nearest_point = text3D.val().solids(
    cq.selectors.NearestToPointSelector((0, 0, 0))
)

There are several ways to access the solids. It depends on your criteria for selection.
Here is an example sorting by volume with the Workplane sort method:

letters_by_vol = text3D.solids().sort(cq.Shape.Volume)
letter_largest_vol = letters_by_vol[-1]

[huskier]

@lorenzncode Thank you for your help.

These methods are able to access the individual solid in the text3D Compound; however, we want to manipulate the individual solid which then affect the original text3D Compound. For example, we want to translate the letter "O" 100 in Z direction, and then we could get the changed text3D object with "O" letter translated 100 in Z direction. Can we achieve this effect with CadQuery?

import cadquery as cq
from cadquery.vis import show

text_string = "Hello, CadQuery!"
font = "Arial"
size = 10  # in millimeters
text3D = cq.Workplane("XZ").text(text_string, combine = True, font = font, fontsize = size, distance = 2).val()

letter_o = [*text3D][4]
letter_o.translate((0, 0, 100))
show(text3D)

letter_nearest_point = text3D.solids(
    cq.selectors.NearestToPointSelector((0, 0, 0))
)
letter_nearest_point.translate((0, 0, 100))
show(text3D)

[adam-urbanczyk]

Currently a copy is made (I think in OCP, TBC). You'd need to recreate the compoud:

letters = list(text3D)
letters[0].move(z=10)
text3D = compound(letters)

[huskier]

letters = list(text3D)
letters[0].move(z=10)
text3D = compound(letters)

That's exactly what we want.

The code you provided could run as expected when the Compound is directly made by our own code; However, when the Compound object is imported from a STEP file (saved from our own code), then, we can not unpack the Compound object. The following is the MVP code. The STEP file "text_Hello_CadQuery_3D_asm.step" is saved from the commented code. We are working on an exploding function, and we need to access and manipulate both the Compound and the objects in the Compound.

import cadquery as cq
from cadquery.vis import show
from cadquery.occ_impl.shapes import compound

text_string = "Hello, CadQuery!"
font = "Arial"
size = 10  # in millimeters
text3D = cq.Workplane("XZ").text(text_string, combine = True, font = font, fontsize = size, distance = 2).val()

# letters = list(text3D)
# letters[0].move(z=10)
# text3D = compound(letters)
# show(text3D)

# text_Hello_3D_asm = (
#     cq.Assembly()
#     .add(letters[0], color = cq.Color(1, 1, 0), name = "H")
#     .add(letters[1], color = cq.Color(1, 1, 0), name = "e")
#     .add(letters[2], color = cq.Color(1, 1, 0), name = "l1")
#     .add(letters[3], color = cq.Color(1, 1, 0), name = "l2")
#     .add(letters[4], color = cq.Color(1, 1, 0), name = "o")
#     .add(letters[5], color = cq.Color(1, 1, 0), name = ",")
# )
# show(text_Hello_3D_asm)

# text_CadQuery_3D_asm = (
#     cq.Assembly()
#     .add(letters[6], color = cq.Color(1, 1, 0), name = "C")
#     .add(letters[7], color = cq.Color(1, 1, 0), name = "a")
#     .add(letters[8], color = cq.Color(1, 1, 0), name = "d")
#     .add(letters[9], color = cq.Color(1, 1, 0), name = "Q")
#     .add(letters[10], color = cq.Color(1, 1, 0), name = "u")
#     .add(letters[11], color = cq.Color(1, 1, 0), name = "e")
#     .add(letters[12], color = cq.Color(1, 1, 0), name = "r")
#     .add(letters[13], color = cq.Color(1, 1, 0), name = "y")
#     .add(letters[14], color = cq.Color(1, 1, 0), name = "!")
# )
# show(text_CadQuery_3D_asm)

# text_Hello_CadQuery_3D_asm = (
#     cq.Assembly()
#     .add(text_Hello_3D_asm, color = cq.Color(1, 1, 0), name = "Hello")
#     .add(text_CadQuery_3D_asm, color = cq.Color(1, 1, 0), name = "CadQuery")
# )
# show(text_Hello_CadQuery_3D_asm)
# text_Hello_CadQuery_3D_asm.save("text_Hello_CadQuery_3D_asm.step")

# text_Hello_CadQuery_3D = text_Hello_CadQuery_3D_asm.toCompound()
# text_Hello_CadQuery_3D_list = list(text_Hello_CadQuery_3D)
# print(len(text_Hello_CadQuery_3D_list))
# show(text_Hello_CadQuery_3D_list[0])
# show(text_Hello_CadQuery_3D_list[1])

# sub_text_Hello_CadQuery_3D_list = list(text_Hello_CadQuery_3D_list[0])
# print(len(sub_text_Hello_CadQuery_3D_list))
# show(sub_text_Hello_CadQuery_3D_list[0])
# show(sub_text_Hello_CadQuery_3D_list[1])

# The result of the above code is as expected! 

# The following code is not as expected. We expect that the text_Hello_CadQuery_3D_list  should be 2 at least, 
# but we get 1 instead.
text_Hello_CadQuery_3D = (
        cq.importers
        .importStep("text_Hello_CadQuery_3D_asm.step")
)
text_Hello_CadQuery_3D = text_Hello_CadQuery_3D.val()
print(type(text_Hello_CadQuery_3D))
show(text_Hello_CadQuery_3D)

show([*text_Hello_CadQuery_3D][0])
#show([*text_Hello_CadQuery_3D][1])

text_Hello_CadQuery_3D_list = list(text_Hello_CadQuery_3D)
print(len(text_Hello_CadQuery_3D_list))

[lorenzncode]

Try flattening the compound, something like this:

def flatten(obj):
    if not isinstance(obj, Compound):
        yield obj
    else:
        for child in obj:
            yield from flatten(child)


print(len(list(flatten(text_Hello_CadQuery_3D))))  # 16

[huskier]

@lorenzncode Thank you for your help.

The flatten function has partially solved the problem. However, the flatten function can not keep the feature tree's hierarchical structure.

Right now, the flatten function could be my first stage solution.

Thank you for both of you, @adam-urbanczyk and @lorenzncode.