doc/salome/examples/complex_objs_ex08.py

   1 # Creation of a PipeBiNormalAlongVector
   2 import salome
   3 salome.salome_init_without_session()
   4 import GEOM
   5 from salome.geom import geomBuilder
   6 geompy = geomBuilder.New()
   7
   8 def MakeSpring(radius, height, rotation, direction, thread_radius, base_rotation, geom_builder):
   9
  10     def MakeHelix(radius, height, rotation, direction, geom_builder):
  11         #  - create a helix -
  12         radius = 1.0 * radius
  13         height = 1.0 * height
  14         rotation = 1.0 * rotation
  15         if direction > 0:
  16             direction = +1
  17         else:
  18             direction = -1
  19             pass
  20         from math import sqrt
  21         length_z  = height
  22         length_xy = radius*rotation
  23         length = sqrt(length_z*length_z + length_xy*length_xy)
  24         nb_steps = 1
  25         epsilon = 1.0e-6
  26         while 1:
  27             z_step = height / nb_steps
  28             angle_step = rotation / nb_steps
  29             z = 0.0
  30             angle = 0.0
  31             helix_points = []
  32             for n in range(nb_steps+1):
  33                 from math import cos, sin
  34                 x = radius * cos(angle)
  35                 y = radius * sin(angle)
  36                 p = geom_builder.MakeVertex(x, y, z)
  37                 helix_points.append( p )
  38                 z += z_step
  39                 angle += direction * angle_step
  40                 pass
  41             helix = geom_builder.MakeInterpol(helix_points)
  42             length_test = geom_builder.BasicProperties(helix)[0]
  43             prec = abs(length-length_test)/length
  44             # print nb_steps, length_test, prec
  45             if prec < epsilon:
  46                 break
  47             nb_steps *= 2
  48             pass
  49         return helix
  50
  51     #  - create a pipe -
  52     thread_radius = 1.0 * thread_radius
  53     # create a helix
  54     helix = MakeHelix(radius, height, rotation, direction, geom_builder=geom_builder)
  55     # base in the (Ox, Oz) plane
  56     p0 = geom_builder.MakeVertex(radius-3*thread_radius, 0.0, -thread_radius)
  57     p1 = geom_builder.MakeVertex(radius+3*thread_radius, 0.0, -thread_radius)
  58     p2 = geom_builder.MakeVertex(radius+3*thread_radius, 0.0, +thread_radius)
  59     p3 = geom_builder.MakeVertex(radius-3*thread_radius, 0.0, +thread_radius)
  60     e0 = geom_builder.MakeEdge(p0, p1)
  61     e1 = geom_builder.MakeEdge(p1, p2)
  62     e2 = geom_builder.MakeEdge(p2, p3)
  63     e3 = geom_builder.MakeEdge(p3, p0)
  64     w = geom_builder.MakeWire([e0, e1, e2, e3])
  65     # create a base face
  66     base = geom_builder.MakeFace(w, True)
  67     # create a binormal vector
  68     binormal = geom_builder.MakeVectorDXDYDZ(0.0, 0.0, 10.0)
  69     # create a pipe
  70     spring = geom_builder.MakePipeBiNormalAlongVector(base, helix, binormal)
  71     # Publish in the study
  72     geom_builder.addToStudy(base, "base")
  73     geom_builder.addToStudy(helix, "helix")
  74     geom_builder.addToStudy(binormal, "binormal")
  75     geom_builder.addToStudy(spring, "spring")
  76     return spring
  77
  78 from math import pi
  79 spring = MakeSpring(50, 100, 2*pi, 1, 5, pi/2, geom_builder=geompy)