OSWG Profile Generation

oswg_profile.py

import math
import FreeCAD, FreeCADGui, Part


# R(x) = sqrt(R0^2 + 2*R0*tan(F)*x + (tan(A)*x)^2)
#
# x     .. distance from the throat along the WG axis
# R(x)  .. radius of the WG at x
# R0    .. radius of the WG at the throat
# A     .. coverage angle
# F     .. initial angle
#

class OSWGProfile:
    def __init__(self, throatRadius, throatAngleDegrees, coverageAngleDegreesVertical, coverageAngleDegreesHorizontal, depth, resolution = 32):
        self.throatRadius= throatRadius
        self.throatAngle = math.radians(throatAngleDegrees)
        self.coverageAngleVertical = math.radians(coverageAngleDegreesVertical)
        self.coverageAngleHorizontal = math.radians(coverageAngleDegreesHorizontal)
        self.depth = depth
        self.resolution = resolution

    def _radius_at(self, coverageAngle, distance):
        return math.sqrt(
                math.pow(self.throatRadius, 2) +
                (2 * self.throatRadius * math.tan(self.throatAngle) * distance) +
                math.pow(math.tan(coverageAngle) * distance, 2)
                )

    def _gen_profile(self, angle):
        return map(
            lambda distance: (distance, self._radius_at(angle, distance)),
            map(
                lambda step: float(step) / self.resolution,
                range(self.depth * self.resolution + 1))
            )

    def _profile_vectors(self, angle, (direction_x, direction_y)):
        return map(
            lambda (distance, radius): (direction_x * radius, direction_y * radius, distance),
            self._gen_profile(angle)
            )

    def top_profile(self):
        return self._profile_vectors(self.coverageAngleVertical, (0, 1))

    def bottom_profile(self):
        return self._profile_vectors(self.coverageAngleVertical, (0, -1))

    def left_profile(self):
        return self._profile_vectors(self.coverageAngleHorizontal, (-1, 0))

    def right_profile(self):
        return self._profile_vectors(self.coverageAngleHorizontal, (1, 0))

    def horizontal_mouth_size(self):
        return self._radius_at(self.coverageAngleHorizontal, self.depth)

    def vertical_mouth_size(self):
        return self._radius_at(self.coverageAngleVertical, self.depth)


def buildPolygon(pointList):
	curve = Part.BSplineCurve()
	curve.interpolate(map(
		lambda (x,y,z): FreeCAD.Vector(x,y,z),
		pointList
		))
	return Part.Wire(curve.toShape())
'''
	return Part.makePolygon(
		map(
			lambda (x,y,z): FreeCAD.Vector(x,y,z),
			pointList
			)
		)
'''

#    curve = Part.BezierCurve()
#    print pointList
#    vectors = map(
#            lambda (x, y, z): FreeCAD.Vector(x, y, z),
#            pointList)
#    curve.setPoles(vectors)
#    return curve.toShape()


waveguide = OSWGProfile(
    12.7,
    5,
    40,
    60,
    100,
    50
)

FreeCAD.ActiveDocument.addObject('Part::Feature', 'OSWG-curve-top').Shape = buildPolygon(waveguide.top_profile())
FreeCAD.ActiveDocument.addObject('Part::Feature', 'OSWG-curve-bottom').Shape = buildPolygon(waveguide.bottom_profile())
FreeCAD.ActiveDocument.addObject('Part::Feature', 'OSWG-curve-left').Shape = buildPolygon(waveguide.left_profile())
FreeCAD.ActiveDocument.addObject('Part::Feature', 'OSWG-curve-right').Shape = buildPolygon(waveguide.right_profile())

throat = FreeCAD.ActiveDocument.addObject('Part::Circle', 'OSWG-throat')
throat.Radius = waveguide.throatRadius

mouth = FreeCAD.ActiveDocument.addObject('Part::Ellipse', 'OSWG-mouth')
mouth.MinorRadius = waveguide.vertical_mouth_size()
mouth.MajorRadius = waveguide.horizontal_mouth_size()
mouth.Placement.move(FreeCAD.Vector(0, 0, waveguide.depth))