Cargo4286

    from ocp_vscode import show_all
    from build123d import *

    od, p, n, d, e = 10 * MM, 12 * MM, 5, 1 * MM, 15 * MM
    base_helix = Helix(p, 2.2 * p, od / 2 + 0.001, center=(0, 0, -p))
    # retain a small piece below XY plane for orienting sketch
    trim_base_helix = base_helix.trim(0.4, 1)
    trim2_base_helix = trim_base_helix.trim(0, 0.72)

    p0 = trim2_base_helix @ 1
    t0 = (trim2_base_helix % 1).normalized()
    t1 = Vector(0, 1, 0).normalized()

    bisector = (t0 + t1).normalized()
    if bisector.length == 0:
        bisector = t0  # Fallback if tangents are perfectly opposite

    ray = Axis(p0, bisector)
    end_pt = ray.intersect(Plane.XZ)

    transition_arc = TangentArc(p0, end_pt, tangent=t0)

    rh_curve = Curve() + [trim2_base_helix, transition_arc]
    profile = (rh_curve ^ 0) * Rot(Z=99) * Circle(d)  # rotate seam out of the way
    rh_sweep = sweep(profile, rh_curve)
    splitter = Plane.XZ * Rectangle(10, 40, align=(Align.MIN, Align.CENTER)).face()
    rh_sweep = split(rh_sweep, bisect_by=splitter, keep=Keep.BOTH).solids()[1]
    lh_sweep = mirror(rh_sweep, about=Plane.XZ)

    both_sweeps = Part() + [rh_sweep, lh_sweep]

    cyl = Part() + Cylinder(od / 2, p + e + d / 2)
    cyl -= both_sweeps
    cyl = split(cyl, bisect_by=Plane.XY)
    cyl += mirror(cyl, about=Plane.XY)
    show_all()

    from build123d import *
    mat = Matrix([[2,0,0,0],[0,1.5,0,0],[0,0,0.5,0]])
    ellipsoid = Sphere(100).transform_geometry(mat)

build123d[1] is based on the same kernel as FreeCAD and has full support for complex filleting situations. Furthermore it also has first class support for 1D and 2D primitives which enable a more flexible design approach.

> The morphological ops in OpenSCAD (minkowski type stuff) are a very poor substitute to real fillets, and are extremely slow (underlying algos are all polynomials in number of triangles) when your objects get complex, and they are global operations, it is extremely hard to limit their action to a localized part of your object.

Agreed.

> Another thing that's a real pain in OpenSCAD: you cannot "probe" (measure) your existing object at a certain stage, grab the result of that measurement and re-use it in the rest of the code. MAJOR limitation.

This is another area where build123d excels. You can create a line and query its length. You can create a face and query its area, position, size, bounding box, etc. You can select parts of a solid and perform operations on them (like a chamfer/fillet, or use them as a reference for positioning). You can query the geometric type of any topological entity; e.g. is this curve linear, a circular arc, elliptical, or a spline?

build123d is IMHO easily one of the most powerful CAD packages that are not well known by a wide audience (owing in part to its ~3 year history). OpenSCAD is a fantastic tool; it was my introduction to CodeCAD and I used it for years. Therefore, my objection isn't to OpenSCAD itself, but to the limitations inherent in any single tool -- and in this case, those limitations are quite significant.