Request: bare show_object() without relying on external editor

[gordon-quad]

Would be nice to have functionality similar to CadQuery/cadquery#1366

To be able to call build123d.vis.show_object() that will pop up VTK viewport without relying on any external software.

[gumyr]

What is the advantage of doing:

from cadquery.vis import show

vs.

from ocp_vscode import show

? Is it that cadquery.vis gets installed with cadquery?

[gordon-quad]

I do not have VSCode and have no intention of using it. It would be nice to be able to use build123d straight from Vim without any extra dependencies.

cadquery.vis is installed with cadquery, I can get my part displayed by just running python cadquery_part.py:

from cadquery import *
from cadquery.vis import show

show(Workplane().box(1,1,1))

[gordon-quad]

I would gladly do it myself, however i would really appreciate some guiding. If you point me out to what sort of changes need to be done with the show func, can help immensely.

I tried to wrap my head around what changes has been made in https://github.com/jdegenstein/jmwright-CQ-Editor vs. original https://github.com/CadQuery/CQ-editor however formatting changes there do not help with comprehension. Also not sure what should I replace the stuff imported from .occ_impl with.

[gordon-quad]

Meanwhile following code works (but requires to have CadQuery installed):

from build123d import *
from cadquery.vis import show_object

with BuildPart() as box_builder:
    Box(1, 1, 1)
    show_object(box_builder.part.wrapped)

[gumyr]

There is a section in the docs on inter-working with CadQuery here: https://build123d.readthedocs.io/en/latest/tips.html#build123d-cadquery-integration. As both tools share the OCP layer (the Python wrapper of the OpenCascade - OCCT - library) the show_object can't tell the difference between build123d and CadQuery if presented with the wrapped (i.e. the OCP) object.

There are four viewers listed in the docs here: https://build123d.readthedocs.io/en/latest/external.html#editors-viewers There are others like blendquery (https://github.com/uki-dev/blendquery) which aren't listed (I'm not sure build123d support is complete with blendquery and will be happy to add it to the docs) so there are no shortage of viewer solutions.

If one wants to use vim (I've used vi/vim for almost four decades now) this can be done by simply using ocp_vscode as the viewer and editing the code with another tool - when show is executed the VSC window will be updated. I use this when doing a quick visual check of the examples by running a bash loop to execute all the python programs in the examples directory and see them flash on the VSC viewer. However, I would not encourage development with just vim, an IDE provides so much additional information when simply hovering over an object that programming is so much more efficient - but each to their own.

As the viewer can be a lot of work (both in development and support) I'm not in a position to take on this challenge but I'd be happy to have another viewer option for users. As an illustration, bernhard (ocp_vscode) is currently working on a native C++ implementation of the tessellation step which should result in a significant performance improvement.

To handle build123d more natively, there are only a couple things to consider:

1. The topology.py andgeometry.py modules define the basic object classes like Solid, Wire, Face and Plane. All of these objects have a wrapped attribute which contains the OCP object. Therefore, if hasattr(shape, "wrapped") is True pass this wrapped object to the viewer.
2. Builders all have a _obj attribute that is mapped to part, sketch or line for BuildPart, BuildSketch and BuildLine Builders. Thus the same type of hasattr check can be used to find the OCP object from builders. This would allow users to display a builder instance by just doing a show(builder_instance). Sketches are actually more complex as there are both local and global views of the sketch(es) but that could be a refinement to add later.

I appreciate your trying to improve the experience of users by having a built-in viewer. Unfortunately, there is currently a quite steep learning curve for new users.