Docs: Add mention of the "caret" operator (^)

[KilowattSynthesis]

It appears that the term "caret", which describes the ^ symbol, is not currently in the build123d docs.

From an example I stumbled across, it appears that the caret operator moves a plane/flat object to the end of a line (to both its point and facing its tangent).

This would be a great thing to cover near the docs about "sweep", as it's hugely useful for the sweep method.

[jdegenstein]

I agree -- this is planned for inclusion in example 37, it is already also included in this example as well https://build123d.readthedocs.io/en/latest/examples_1.html#handle and also mentioned on the cheat sheet https://build123d.readthedocs.io/en/latest/cheat_sheet.html

[KilowattSynthesis]

I'm struggling to grasp what's going on in that example; it's too bad it's not a bit more intuitive.

I'm looking at the algebraic code.

How does the sections variable get lined up with the handle_center_line? Is it strictly based on the location? Or does index play a part? What would happen if those rectangles/circles weren't right on the handle_center_line?

[KilowattSynthesis]

It's also too bad that readthedocs can't handle a search for a caret correctly (i.e., it returns no results): https://build123d.readthedocs.io/en/latest/search.html?q=%5E&check_keywords=yes&area=default

[gumyr]

Here is a detailed explanation of that example provided by ChatGPT 4o (unedited outside of formatting):

This code creates a handle shape by sweeping a series of cross-sectional shapes (circles and rounded rectangles) along a path defined by a spline. Here’s a breakdown of each part:

1. Imports:

   from build123d import *
   from ocp_vscode import show_object

   This imports necessary modules. build123d provides tools for CAD operations, and ocp_vscode is used for visualizing objects.

2. Define segment_count:

   segment_count = 6

   This specifies the number of segments along the handle path. This will determine how many cross-sections are created along the path.

3. Create the Path (handle_center_line):

   handle_center_line = Spline(
       (-10, 0, 0),
       (0, 0, 5),
       (10, 0, 0),
       tangents=((0, 0, 1), (0, 0, -1)),
       tangent_scalars=(1.5, 1.5),
   )

   A 3D spline path is created for the handle’s central line. The path starts at (-10, 0, 0), arcs upwards to (0, 0, 5), and ends at (10, 0, 0). Tangents are specified at each end to control the slope, with scalar values that adjust the influence of each tangent.

4. Define Cross-Sections (sections):

   sections = Sketch()
   for i in range(segment_count + 1):
       location = handle_center_line ^ (i / segment_count)
       if i % segment_count == 0:
           circle = location * Circle(1)
       else:
           circle = location * Rectangle(1.25, 3)
           circle = fillet(circle.vertices(), radius=0.2)
       sections += circle

   This loop creates cross-sections at intervals along the spline path:

   • location = handle_center_line ^ (i / segment_count): Places each cross-section along the path using parametric division.
   • if i % segment_count == 0: If it’s the first or last section, a circular cross-section with radius 1 is created.
   • For other sections, a rectangular cross-section (1.25 x 3) is created, and filleting (rounded corners) is applied to the vertices with a radius of 0.2.
   • Each cross-section is added to sections, forming the series of shapes to be swept along the handle path.

5. Sweep Operation to Create the Handle (handle):

   handle = sweep(sections, path=handle_center_line, multisection=True)

   The sweep function uses sections as the cross-sections and handle_center_line as the path, creating a 3D handle by sweeping the cross-sections along the spline. multisection=True enables smooth transition between different shapes along the path.

6. Visualize the Objects:

   show_object(handle_center_line, name="handle_path")
   for i, circle in enumerate(sections):
       show_object(circle, name="section" + str(i))
   show_object(handle, name="handle", options=dict(alpha=0.6))

   • handle_center_line is displayed as the path of the handle.
   • Each cross-section is displayed with labels like section0, section1, etc.
   • The final 3D handle object is displayed with 60% transparency (alpha set to 0.6).

Overall, this code demonstrates how to model a handle shape in build123d by defining a path and sweeping different cross-sectional profiles along it.

[KilowattSynthesis]

I can read the code haha, thank you though.

How does the sections variable get lined up with the handle_center_line? Is it strictly based on the location? Or does index play a part? What would happen if those rectangles/circles weren't right on the handle_center_line?

[gumyr]

circle = location * Circle(1) creates a circle positioned at location. Try messing about with the alignment of Circle and Rectangle and see how it changes the sweep (e.g. Circle(1, align=Align.MIN).