(Part 2/3) Project 3D part to plane

[antonysigma]

Simulate the API from Build123d project_to_viewpoint: Given a 3D vector representing the camera position pointing at the origin (0,0,0), render all visible edges/arcs/splines representing the outline of the 3D part projected to the camera.

Also render all hidden edges/arcs/splines.

Provide and example script tests/test_projection.py where a generic part (A bracket with rounded corners and a countersunk hole) is projected to top view, side view, front view, and orthogonal view, and then exported to DXF 2D drawings.

Reference: https://build123d.readthedocs.io/en/latest/tech_drawing_tutorial.html

Expected output from tests/test_projection.py:

Follow-up of MR #2001 .
Related to: #122, #1767

[adam-urbanczyk]

OK, let's get this going. @antonysigma could you run our version of black in the codebase?

[antonysigma]

OK, let's get this going. @antonysigma could you run our version of black in the codebase?

Done running black and pushed the new commit. Let me know if you need anything else.

[adam-urbanczyk]

Still failing on black, did you use our version of the tool?

[antonysigma]

Still failing on black, did you use our version of the tool?

My apologies. I mixed up darker with black. I pushed the revisions again.

[adam-urbanczyk]

OK, next step to make the CI green is to fix mypy errors. Are you up to it @antonysigma ?

[antonysigma]

OK, next step to make the CI green is to fix mypy errors. Are you up to it @antonysigma ?

I can help resolve new mypy errors caused by this PR, but I don't where the rest of the errors originated from. Were those errors introduced before my PR? Could you teach me how to program Appveyor's CI to ignore errors before my PR?

[adam-urbanczyk]

There are no mypy issues on HEAD according to our CI. So I assume that everything is on your side. No need to do anything with appveyor,, you can run mypy locally and simply fix all the errors. If this sounds too complicated, we can probably help.

[antonysigma]

Hi @adam-urbanczyk ,

Yes, I need help resolving mypy errors, especially those exists before this PR.

Please refer to the inline comments for the out-of-scope errors.

-Antony

[codecov]

Codecov Report

❌ Patch coverage is 97.75281% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.70%. Comparing base (3e34909) to head (0e03c1c).

Files with missing lines	Patch %	Lines
cadquery/occ_impl/exporters/dxf.py	81.81%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2002   +/-   ##
=======================================
  Coverage   95.70%   95.70%           
=======================================
  Files          30       30           
  Lines        9447     9479   +32     
  Branches     1406     1410    +4     
=======================================
+ Hits         9041     9072   +31     
- Misses        252      253    +1     
  Partials      154      154           

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[antonysigma]

Thank you for doing the dirty laundry for me. It is certainly a daunting process for me to understand the legacy DXF code in the repo, not to mention patching it. I appreciate the effort.

[lorenzncode]

@antonysigma This results in the same result as your DXF screenshot from the description above:

exporters.exportDXFProjection(drilled, "ortho.dxf", (1, 1, 1))

Now you also have the option to specify "up" direction.

exporters.exportDXFProjection(drilled, "ortho_zup.dxf", (1, 1, 1), up=(0, 0, 1))

[lorenzncode]

Example generating a PNG screenshot with cadquery.vis:

from cadquery import Workplane
from cadquery.func import hlr
from cadquery.vis import show, style

# Based on examples/Ex102_DXF_with_HLR.py.
width = 10
depth = 10
height = 10
hole_dia = 3.0

baseplate = Workplane("XY").box(width, depth, height).edges("|Z").fillet(2.0)
drilled = baseplate.faces(">Z").workplane().cskHole(hole_dia, hole_dia * 2, 82.0)

# Create an isometric orthographic projection with world +Z pointing upward.
hlr_result = hlr(drilled.val(), (1, -1, 1), up=(0, 0, 1))

show(
    style(hlr_result.visible, edgecolor="black", markersize=0),
    style(hlr_result.hidden, edgecolor="gray", linewidth=1, markersize=0,),
    interact=False,
    screenshot="img.png",
    width=800,
    height=800,
    roll=0,
    elevation=0,
    trihedron=False,
    gradient=False,
    bgcolor=(1, 1, 1),  # (this is also default color)
)

[antonysigma]

@lorenzncode Thanks for refactoring the projection APIs. I haven't run the new example code on my computer yet, but I looks good to me at first glance. Feel free to merge it.

There is also Part 3/3 of the 2D projection feature: orthogonal projections and titlecard generation for 2D CAD drawings. I will rebase my branch to this PR later to make use of the modified APIs, before submitting the part 3 PR for code review.

[adam-urbanczyk]

@lorenzncode LGTM, shall we merge?

[lorenzncode]

Yes, ready to merge.

[antonysigma]

@lorenzncode @jmwright @adam-urbanczyk I just submitted the draft PR, showcasing the final integration to the technical drawing feature. That should represent almost all of my use-cases for the API cq.exporters.exportDXFProjection.

Question: how do I configure Github PR webpage to "rebase" to this PR? Or, make this PR the dependency?

#2068

[adam-urbanczyk]

Not sure what you mean. Just merge master to your branch and it should be fine.