geom/doc/salome/examples/complex_objs_ex08.py

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2013-02-12 17:35:16 +06:00
# Creation of a PipeBiNormalAlongVector
def MakeHelix(radius, height, rotation, direction):
# - create a helix -
radius = 1.0 * radius
height = 1.0 * height
rotation = 1.0 * rotation
if direction > 0:
direction = +1
else:
direction = -1
pass
from math import sqrt
length_z = height
length_xy = radius*rotation
length = sqrt(length_z*length_z + length_xy*length_xy)
import geompy
nb_steps = 1
epsilon = 1.0e-6
while 1:
z_step = height / nb_steps
angle_step = rotation / nb_steps
z = 0.0
angle = 0.0
helix_points = []
for n in range(nb_steps+1):
from math import cos, sin
x = radius * cos(angle)
y = radius * sin(angle)
p = geompy.MakeVertex(x, y, z)
helix_points.append( p )
z += z_step
angle += direction * angle_step
pass
helix = geompy.MakeInterpol(helix_points)
length_test = geompy.BasicProperties(helix)[0]
prec = abs(length-length_test)/length
# print nb_steps, length_test, prec
if prec < epsilon:
break
nb_steps *= 2
pass
return helix
def MakeSpring(radius, height, rotation, direction, thread_radius, base_rotation=0.0):
# - create a pipe -
thread_radius = 1.0 * thread_radius
# create a helix
helix = MakeHelix(radius, height, rotation, direction)
# base in the (Ox, Oz) plane
import geompy
p0 = geompy.MakeVertex(radius-3*thread_radius, 0.0, -thread_radius)
p1 = geompy.MakeVertex(radius+3*thread_radius, 0.0, -thread_radius)
p2 = geompy.MakeVertex(radius+3*thread_radius, 0.0, +thread_radius)
p3 = geompy.MakeVertex(radius-3*thread_radius, 0.0, +thread_radius)
e0 = geompy.MakeEdge(p0, p1)
e1 = geompy.MakeEdge(p1, p2)
e2 = geompy.MakeEdge(p2, p3)
e3 = geompy.MakeEdge(p3, p0)
w = geompy.MakeWire([e0, e1, e2, e3])
# create a base face
base = geompy.MakeFace(w, True)
# create a binormal vector
binormal = geompy.MakeVectorDXDYDZ(0.0, 0.0, 10.0)
# create a pipe
spring = geompy.MakePipeBiNormalAlongVector(base, helix, binormal)
# Publish in the study
geompy.addToStudy(base, "base")
geompy.addToStudy(helix, "helix")
geompy.addToStudy(binormal, "binormal")
geompy.addToStudy(spring, "spring")
return spring
from math import pi
spring = MakeSpring(50, 100, 2*pi, 1, 5, pi/2)