doc/salome/examples/complex_objs_ex08.py

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