Workplane translate does not move the tags

[lenianiva]

Consider this example which should produce 3 cubes stacked on top of each other:

import cadquery as Cq

def tagged_box(tag=""):
    result = (
        Cq.Workplane('XY')
        .box(10, 10, 10)
    )
    result.faces("<Z").tag(f"{tag}bot")
    result.faces(">Z").tag(f"{tag}top")
    return result

def tagged_double_box():
    result = (
        tagged_box("b1_")
        .union(
            tagged_box("b2_")
            .translate((0, 0, 5))
            .rotate((0, 0, 0), (0, 0, 1), 45)
        )
    )
    return result

result = (
    Cq.Assembly()
    .add(tagged_box(), name="parent", color=Cq.Color("blue1"))
    .add(tagged_double_box(), name="child", color=Cq.Color("yellow1"))
    .constrain("parent?bot", "child?b2_top", "Plane")
    .solve()
)

show_object(result)

but instead the mating surface child?b2_top stays in place, despite that the object was moved up by 5mm.

Is this intended behaviour? How can I get the tag b2_top to move during .translate()?

One solution here is to use sub-assemblies.

[lorenzncode]

Methods such as translate create new Workplane objects in the chain.

See also docs introspective example for more. It should help with tags usage. https://cadquery.readthedocs.io/en/latest/primer.html#an-introspective-example:
Returning a new instance of Workplane is the normal behaviour of most Workplane methods...
Tags offer a way to refer back to a previous Workplane

[lenianiva]

Methods such as translate create new Workplane objects in the chain.

See also docs introspective example for more. It should help with tags usage. https://cadquery.readthedocs.io/en/latest/primer.html#an-introspective-example: Returning a new instance of Workplane is the normal behaviour of most Workplane methods... Tags offer a way to refer back to a previous Workplane

Is there a way to move all objects in a workplane while preserving the tags?

[lorenzncode]

Yes, it's possible. There is no built-in method, but can be done as follows:

1. Iterate over <the Workplane>.ctx.tags.values()
2. Directly update each tagged Workplane object list (translate each object)