packer - a ball packer

Usage | Examples | Notes

Usage

Synopsis

packer [options] [ball_rad [container_rad [inner_rad]]]

Pack balls in a sphere, or between two concentric spheres. The pack is seeded with two or more balls, then subsequent balls are added one at a time in three point contact in positions chosen by the packing method until no more balls may be added.

Options

ball_rad: ball radius
container_rad: spherical container radius (default: 1)
inner_rad: inner spherical container radius (default: no inner container)

-h

program help

-m <mthd>

packing method

up - bottom up (default)
in - outside to centre
out - centre to outside
inup - outside in bottom
outup - centre to outside bottom first.
around - nearest to x=0 rotating around y-axis
laround - nearest to last ball rotating around y-axis
earlist - touching earliest placed ball

-l

alway pack each ball in contact with last placed ball

-n <num>

maximum number of balls to pack (default:pack all)

-a <num>

maximum number of balls to add to pack, repecting -N (default:pack all)

-M

use centre of mass for methods using a centre

-i <file>

input file containing coordinates of the seed balls

-f

frames, write output file of the form ./packer_out_0052.off (the number is the number of balls) every time a ball is added

-o <file>

write output to file, if this option is not used the program writes to standard output

Examples

Pack unit radius balls in a 5 unit radius sphere, pack nearest to the centre, use the default seed for this method (a central ball and two other balls all mutually in contact), write output to pk.off.

   packer -m out -o pk.off 1 5

Notes

Here is a short Python script as a demonstration of how to make images of the frames created with the -f option using POV-ray.


import os
import glob

i=0
for off_file in glob.glob('./packer_out_[0-9][0-9][0-9][0-9].off'):
   pov_file = "panim_%04d.pov" % i
   os.system("off2pov -v b -x ef -D 10.5 -C 0,0,0 -R 25,10,0 -o %s %s" %(pov_file, off_file))
   os.system("povray +a %s" % pov_file)
   i +=1

These could be combined into a GIF animation using the ImageMagick convert program.

   convert panim*.png pack_anim.gif

Up: Programs and Documentation
Next: string_art - string figures

Antiprism Documentation 15.6.2005 - http://www.antiprism.com/