def test_Fitting(self):
# Collinear points should not define a plane.
a = Gf.Vec3d(0, 0, 0)
b = Gf.Vec3d(1, 0, 0)
c = Gf.Vec3d(2, 0, 0)
self.assertIsNone(Gf.FitPlaneToPoints([a, b, c]), err("collinear"))
# Cannot fit plane to 2 or fewer points.
with self.assertRaises(Tf.ErrorException):
Gf.FitPlaneToPoints([a, b])
# Perfect fit (normal should be parallel to Z-axis, but OK if opposite
# direction).
c = Gf.Vec3d(0, 1, 0)
p = Gf.FitPlaneToPoints([a, b, c])
self.assertAlmostEqual(Gf.Dot(p.GetNormal(), Gf.Vec3d.ZAxis()), 1.0,
msg=err("normal1"))
self.assertAlmostEqual(p.GetDistanceFromOrigin(), 0.0,
msg=err("distance1"))
# Try the same plane but with non-unit vectors.
b = Gf.Vec3d(1.5, 0, 0)
c = Gf.Vec3d(0, 3.2, 0)
p = Gf.FitPlaneToPoints([a, b, c])
self.assertAlmostEqual(Gf.Dot(p.GetNormal(), Gf.Vec3d.ZAxis()), 1.0,
msg=err("normal2"))
self.assertAlmostEqual(p.GetDistanceFromOrigin(), 0.0,
msg=err("distance2"))
# Try a more complicated plane.
p1 = Gf.Plane(Gf.Vec4d(3, 4, 0, 5)) # equation constructor
a = p1.Project(Gf.Vec3d(2, 3, 6))
b = p1.Project(Gf.Vec3d(34, -2, 2))
c = p1.Project(Gf.Vec3d(-3, 7, -8))
d = p1.Project(Gf.Vec3d(4, 1, 1))
e = p1.Project(Gf.Vec3d(87, 67, 92))
p2 = Gf.FitPlaneToPoints([a, b, c])
self.assertAlmostEqual(
Gf.Dot(p1.GetNormal(), p2.GetNormal()), 1.0,
msg=err("p2 normal parallel to p1"))
self.assertAlmostEqual(
p1.GetDistanceFromOrigin(),
p2.GetDistanceFromOrigin(),
msg=err("p2 distance equals p1"))
p3 = Gf.FitPlaneToPoints([a, b, c, d, e])
self.assertAlmostEqual(
Gf.Dot(p1.GetNormal(), p3.GetNormal()), 1.0,
msg=err("p3 normal parallel to p1"))
self.assertAlmostEqual(
p1.GetDistanceFromOrigin(),
p3.GetDistanceFromOrigin(),
msg=err("p3 distance equals p1"))
# Try fitting points that don't form a perfect plane.
# This roughly forms the plane with normal (1, -1, 0) passing through
# the origin.
# Decrease the number of places of accuracy since these points are
# fudged and don't form an exact plane.
a = Gf.Vec3d(1.1, 1, 5)
b = Gf.Vec3d(1, 1.1, 2)
c = Gf.Vec3d(2, 2.1, -4)
d = Gf.Vec3d(2.1, 2, 1)
e = Gf.Vec3d(25.3, 25.2, 3)
f = Gf.Vec3d(25.1, 25.4, 6)
p = Gf.FitPlaneToPoints([a, b, c, d, e, f])
expectedNormal = Gf.Vec3d(1, -1, 0).GetNormalized()
self.assertAlmostEqual(
Gf.Dot(p.GetNormal(), expectedNormal), 1.0,
places=2,
msg=err("normal3"))
self.assertAlmostEqual(
p.GetDistanceFromOrigin(), 0.0,
places=2,
msg=err("distance3"))
