![[tokkee]](http://tokkee.org/images/avatar.png){kind=avatar}
index c60f63b8312b24cb68d42a2f039d2ddc7028047a..a1b3ee666d4b6bb4cd02390f2bd6dd261d7a7556 100644 (file)
-#!/usr/bin/env python
+#! /usr/bin/env python
'''
Copyright (C) 2007 Aaron Spike (aaron @ ekips.org)
Copyright (C) 2007 Tavmjong Bah (tavmjong @ free.fr)
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-'''\r
+'''
import inkex
import simplestyle, sys
from math import *
+import string
def involute_intersect_angle(Rb, R):
Rb, R = float(Rb), float(R)
def __init__(self):
inkex.Effect.__init__(self)
self.OptionParser.add_option("-t", "--teeth",
- action="store", type="int",
+ action="store", type="int",
dest="teeth", default=24,
help="Number of teeth")
self.OptionParser.add_option("-p", "--pitch",
- action="store", type="float",
+ action="store", type="float",
dest="pitch", default=20.0,
help="Circular Pitch (length of arc from one tooth to next)")
self.OptionParser.add_option("-a", "--angle",
- action="store", type="float",
+ action="store", type="float",
dest="angle", default=20.0,
help="Pressure Angle (common values: 14.5, 20, 25 degrees)")
+ self.OptionParser.add_option("-c", "--centerdiameter",
+ action="store", type="float",
+ dest="centerdiameter", default=10.0,
+ help="Diameter of central hole - 0.0 for no hole")
+ self.OptionParser.add_option("-u", "--unit",
+ action="store", type="string",
+ dest="unit", default="px",
+ help="unit of measure for circular pitch and center diameter")
def effect(self):
-
+
teeth = self.options.teeth
- pitch = self.options.pitch
+ pitch = inkex.unittouu( str(self.options.pitch) + self.options.unit)
angle = self.options.angle # Angle of tangent to tooth at circular pitch wrt radial line.
+ centerdiameter = inkex.unittouu( str(self.options.centerdiameter) + self.options.unit)
# print >>sys.stderr, "Teeth: %s\n" % teeth
two_pi = 2.0 * pi
-
+
# Pitch (circular pitch): Length of the arc from one tooth to the next)
# Pitch diameter: Diameter of pitch circle.
pitch_diameter = float( teeth ) * pitch / pi
pitch_radius = pitch_diameter / 2.0
-
+
# Base Circle
base_diameter = pitch_diameter * cos( radians( angle ) )
base_radius = base_diameter / 2.0
-
+
# Diametrial pitch: Number of teeth per unit length.
pitch_diametrial = float( teeth )/ pitch_diameter
# Addendum: Radial distance from pitch circle to outside circle.
addendum = 1.0 / pitch_diametrial
-
+
# Outer Circle
outer_radius = pitch_radius + addendum
outer_diameter = outer_radius * 2.0
-
+
# Tooth thickness: Tooth width along pitch circle.
tooth = ( pi * pitch_diameter ) / ( 2.0 * float( teeth ) )
-
+
# Undercut?
undercut = (2.0 / ( sin( radians( angle ) ) ** 2))
needs_undercut = teeth < undercut
-
+
# Clearance: Radial distance between top of tooth on one gear to bottom of gap on another.
clearance = 0.0
# Dedendum: Radial distance from pitch circle to root diameter.
dedendum = addendum + clearance
-
+
# Root diameter: Diameter of bottom of tooth spaces.
root_radius = pitch_radius - dedendum
root_diameter = root_radius * 2.0
-
+
half_thick_angle = two_pi / (4.0 * float( teeth ) )
pitch_to_base_angle = involute_intersect_angle( base_radius, pitch_radius )
pitch_to_outer_angle = involute_intersect_angle( base_radius, outer_radius ) - pitch_to_base_angle
-
+
centers = [(x * two_pi / float( teeth) ) for x in range( teeth ) ]
-
+
points = []
for c in centers:
- # Angles
- pitch1 = c - half_thick_angle
- base1 = pitch1 - pitch_to_base_angle
- outer1 = pitch1 + pitch_to_outer_angle
-
- pitch2 = c + half_thick_angle
- base2 = pitch2 + pitch_to_base_angle
- outer2 = pitch2 - pitch_to_outer_angle
-
- # Points
- b1 = point_on_circle( base_radius, base1 )
- p1 = point_on_circle( pitch_radius, pitch1 )
- o1 = point_on_circle( outer_radius, outer1 )
-
- b2 = point_on_circle( base_radius, base2 )
- p2 = point_on_circle( pitch_radius, pitch2 )
- o2 = point_on_circle( outer_radius, outer2 )
-
- if root_radius > base_radius:
- pitch_to_root_angle = pitch_to_base_angle - involute_intersect_angle(base_radius, root_radius )
- root1 = pitch1 - pitch_to_root_angle
- root2 = pitch2 + pitch_to_root_angle
- r1 = point_on_circle(root_radius, root1)
- r2 = point_on_circle(root_radius, root2)
- p_tmp = [r1,p1,o1,o2,p2,r2]
- else:
- r1 = point_on_circle(root_radius, base1)
- r2 = point_on_circle(root_radius, base2)
- p_tmp = [r1,b1,p1,o1,o2,p2,b2,r2]
-
- points.extend( p_tmp )
+ # Angles
+ pitch1 = c - half_thick_angle
+ base1 = pitch1 - pitch_to_base_angle
+ outer1 = pitch1 + pitch_to_outer_angle
+
+ pitch2 = c + half_thick_angle
+ base2 = pitch2 + pitch_to_base_angle
+ outer2 = pitch2 - pitch_to_outer_angle
+
+ # Points
+ b1 = point_on_circle( base_radius, base1 )
+ p1 = point_on_circle( pitch_radius, pitch1 )
+ o1 = point_on_circle( outer_radius, outer1 )
+
+ b2 = point_on_circle( base_radius, base2 )
+ p2 = point_on_circle( pitch_radius, pitch2 )
+ o2 = point_on_circle( outer_radius, outer2 )
+
+ if root_radius > base_radius:
+ pitch_to_root_angle = pitch_to_base_angle - involute_intersect_angle(base_radius, root_radius )
+ root1 = pitch1 - pitch_to_root_angle
+ root2 = pitch2 + pitch_to_root_angle
+ r1 = point_on_circle(root_radius, root1)
+ r2 = point_on_circle(root_radius, root2)
+ p_tmp = [r1,p1,o1,o2,p2,r2]
+ else:
+ r1 = point_on_circle(root_radius, base1)
+ r2 = point_on_circle(root_radius, base2)
+ p_tmp = [r1,b1,p1,o1,o2,p2,b2,r2]
+
+ points.extend( p_tmp )
path = points_to_svgd( points )
# Embed gear in group to make animation easier:
- # Translate group, Rotate path.\r
- t = 'translate(' + str( self.view_center[0] ) + ',' + str( self.view_center[1] ) + ')'\r
- g_attribs = {inkex.addNS('label','inkscape'):'Gear' + str( teeth ),\r
- 'transform':t }
+ # Translate group, Rotate path.
+ t = 'translate(' + str( self.view_center[0] ) + ',' + str( self.view_center[1] ) + ')'
+ g_attribs = {inkex.addNS('label','inkscape'):'Gear' + str( teeth ),
+ 'transform':t }
g = inkex.etree.SubElement(self.current_layer, 'g', g_attribs)
- # Create SVG Path for gear\r
- style = { 'stroke': '#000000', 'fill': 'none' }\r
+ # Create SVG Path for gear
+ style = { 'stroke': '#000000', 'fill': 'none' }
gear_attribs = {'style':simplestyle.formatStyle(style), 'd':path}
- gear = inkex.etree.SubElement(g, inkex.addNS('path','svg'), gear_attribs )\r
-
-e = Gears()
-e.affect()
-
+ gear = inkex.etree.SubElement(g, inkex.addNS('path','svg'), gear_attribs )
+ if(centerdiameter > 0.0):
+ center_attribs = {'style':simplestyle.formatStyle(style),
+ inkex.addNS('cx','sodipodi') :'0.0',
+ inkex.addNS('cy','sodipodi') :'0.0',
+ inkex.addNS('rx','sodipodi') :str(centerdiameter/2),
+ inkex.addNS('ry','sodipodi') :str(centerdiameter/2),
+ inkex.addNS('type','sodipodi') :'arc'
+ }
+ center = inkex.etree.SubElement(g, inkex.addNS('path','svg'), center_attribs )
+
+if __name__ == '__main__':
+ e = Gears()
+ e.affect()
+
+
+# vim: expandtab shiftwidth=4 tabstop=8 softtabstop=4 fileencoding=utf-8 textwidth=99