Workplane.spline() Doesn't Support Tangents at Arbitrary Interpolation Points

[pavpen]

Hello, developers.

The implementation of Workplane.spline, doesn't seem to support specifying tangents for arbitrary interpolation points, but only at the start and end points. The underlying GeomAPI_Interpolate interpolator does support this feature. (It is also exposed in FreeCAD.)

I would like to add this feature to Workplane.spline(), or, perhaps, to a new method, if changing spline() may cause undesirable breakages.

Let me know, if this sounds like a good idea.

Thanks,

---

Pav

[adam-urbanczyk]

Hey, absolutely! If you want to implement it, I'd propose to just check the length of the tangents in cq.Workplane.spline and in cq.Edge.makeSpline and act accordingly.

[pavpen]

That's what I was doing. I was also adding the parameters argument (I need to figure out how to add some unit tests.):

    @classmethod
    def makeSpline(
        cls: Type["Edge"],
        listOfVector: List[Vector],
        tangents: Optional[Sequence[Vector]] = None,
        periodic: bool = False,
        parameters: Optional[List[float]] = None,
        tol: float = 1e-6,
    ) -> "Edge":
        """
        Interpolate a spline through the provided points.
        :param cls:
        :param listOfVector: a list of Vectors that represent the points
        :param tangents: tuple of Vectors specifying start and finish tangent
        :param periodic: creation of peridic curves
        :param parameters: the value of the parameter at each interpolation point.
            (The intepolated curve is represented as a vector-valued function of a
            scalar parameter.)
                If periodic == True, then len(parameters) must be
            len(intepolation points) + 1, otherwise len(parameters) must be equal to
            len(interpolation points).
        :param tol: tolerance of the algorithm (consult OCC documentation)
                Used to check that the specified points are not too close to each
            other, and that tangent vectors are not too short. (In either case
            interpolation may fail.)
        :return: an Edge
        """

Also, I think passing Scale = False to GeomAPI_Interpolate.Load() would save some unnecessary computation. But that's a minor point.

[marcus7070]

Closed in #636