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[Jan Stránský <question658629@xxxxxxxxxxxxxxxxxxxxx>]

Question #658629 on Yade changed:
https://answers.launchpad.net/yade/+question/658629

Jan Stránský proposed the following answer:
###
def cylSurf(center,radius,height,nSegments=12,thick=0,**kw):
   """creates cylinder made of boxes. Axis is parallel with z+
   center ... center of bottom disc
   radius ... radius of cylinder
   height ... height of cylinder
   nSegments ... number of boxes forming cylinder
   thick ... thickness of the boxes
   **kw ... keywords passed to box function (e.g. material, color ...)
   """
   # just converts (a,b,c) to Vector3(a,b,c) to enable "center + ..."
   center = Vector3(center)
   # nSegments angles to define individual boxes, from 0 to 2*pi
   angles = [i*2*pi/nSegments for i in range(nSegments)]
   # centers of boxes. Vector 3(radius,0,0) rotated by angle 'a'
   # z coordinate is .5*height
   # center + shift = center of corresponding box
   pts = [center + Vector3(radius*cos(a),radius*sin(a),.5*height) for a in angles] # centers of plates
   ret = []
   for i,pt in enumerate(pts): # for each box center create corresponding box
      # "length" of the box along circumference, cylinder circumference / nSegments
      l = pi*radius/nSegments
      # extents, half dimensions along x,y,z axis
      es = (.5*thick,l,.5*height)
      # by default box is axis-aligned, we need to rotate it along z axis (0,0,1) by angle i*2*pi/nSegments
      ori = Quaternion((0,0,1),i*2*pi/nSegments)
      # have a look at utils.box documentation. pt=center of box, es=extents (half dimension), ori=orientation
      ret.append(box(pt,es,ori,**kw))
   return ret
###

you can use print to see the values if you want to understand what is going on. You can also write your function from the scratch.
cheers
Jan

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