DXF export issue

[adam-urbanczyk]

My use-case has a far smaller work scope: I only need 3D-to-2D projections. Dimensions & annotation are not required. Kind of similar to #1685 except in DXF:

Here is my reduced workflow:

1. On-demand 3rd angle projections of the same part to three separate DXF files (e.g. top.dxf, left.dxf, front.dxf)

2. Write a simple (Python/bash) script to embed the DXF files into a ISO titleblock template, e.g. this file

3. Open the output DXF in the LibreCAD GUI.

4. Manually draw dimensions on the titleblock with command prompt or with the mouse.

I managed to simulate #1685 with the following code:

def exportDXF3rdAngleProjection(my_part, prefix: str) -> None:
    viewpoint = {
        'top': (0, 0, 1),
        'left': (1, 0, 0),
        'front': (0, 1, 0),
    }
    for name, direction in viewpoint.items():
        cq.exporters.exportDXF(
            mounting_rail.rotateAboutCenter(direction, 90),
            f"{prefix}{name}.dxf",

            # Note: exportDXF is missing the following parameter.
            #opt={
            #    "projectionDir": direction,
            #},
            doc_units=6,
        )

but the issue is cq.exporters.exportDXF messed up the countersunk holes:

Question: is it a known issue in cadquery? Is there a bug report on Github that I can keep track of?

Originally posted by @antonysigma in #122

[adam-urbanczyk]

@antonysigma could you provide a MRE?

[antonysigma]

could you provide a MRE?

@adam-urbanczyk , here you are. Thanks in advance!

Python version: Python 3.9.5
cadquery version: cadquery==2.5.2

import cadquery as cq
from ocp_vscode import (
    set_port,
    show_object,
)

viewpoint = {
    'top': (0, 0, 1),
    'left': (1, 0, 0),
    'front': (0, 1, 0),
}

def exportDXF3rdAngleProjection(my_part, prefix: str) -> None:
    for name, direction in viewpoint.items():
        cq.exporters.exportDXF(
            my_part.rotateAboutCenter(direction, 90),
            f"{prefix}{name}.dxf",

            # Note: exportDXF is missing the following parameter.
            #opt={
            #    "projectionDir": direction,
            #},
            doc_units=6,
        )

def exportSVG3rdAngleProjection(my_part, prefix: str) -> None:
    for name, direction in viewpoint.items():
        cq.exporters.export(
            my_part,
            f'{prefix}{name}.svg',
            opt={
                'projectionDir': direction,
            },
        )

if __name__ == '__main__':
    # Build the part
    width = 10
    depth = 10
    height = 10.0

    # !!! Test projection of fillets to arc segments in DXF. !!!
    baseplate = (
        cq.Workplane("XY")  #
        .box(width, depth, height)
        .edges("|Z")
        .fillet(2.0)
    )

    hole_dia = 3.0

    # !!! Test projection of countersunk to arc segments in DXF. !!!
    drilled = (
        baseplate.faces(">Z")  #
        .workplane()
        .cskHole(hole_dia, hole_dia * 2, 82.0)
    )

    # Expected DXF output to be identical to SVG output
    exportSVG3rdAngleProjection(drilled, "")
    exportDXF3rdAngleProjection(drilled, "")

    # Initialize the ocp_vscode viewer
    if False:
        set_port(3939)
        show_object(drilled)