doc/salome/examples/complex_objs_ex08.py

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