Converts STL files from/to binary <-> ascii formats

This commit is contained in:
Abhay Rana 2015-02-10 19:33:20 +05:30
parent 016c4595b2
commit baffd09d63
1 changed files with 127 additions and 0 deletions

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convertSTL.rb Executable file
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#!/usr/bin/env ruby
# convertSTL.rb - Converts STL files between binary and ASCII encoding
# by Chris Polis
#
# This script detects which encoding the stl file is in and converts it to
# the opposite encoding and saves the file as *-ascii.stl or *-binary.stl.
# I wrote this script to save disk space and bandwidth when using stl files.
#
# USAGE:
# $ ruby convertSTL.rb [filename of .stl to be converted]
# or 'chmod +x' and run as ./convertSTL.rb
#
# Helper methods
class Float
def to_sn # to scientific notation
"%E" % self
end
def self.from_sn str # generate a float from scientific notation
("%f" % str).to_f
end
end
# Pass in filename as only argument
if ARGV.size != 1
puts "Usage: ./converSTL.rb [stl filename]"
exit
end
# Read file
begin
original = File.new(ARGV[0], "r")
# Read first line - check binary or ASCII
tempLine = original.gets
if tempLine.include? "solid"
outFilename = ARGV[0].sub(/\.stl/i, '-binary.stl')
puts "#{ARGV[0]} is in ASCII format, converting to BINARY: #{outFilename}"
outFile = File.new(outFilename, "w")
outFile.write("\0" * 80) # 80 bit header - ignored
outFile.write("FFFF") # 4 bit integer # of triangles - filled later
triCount = 0
# ASCII STL format (from Wikipedia):
# solid name(optional)
#
# [foreach triangle]
# facet normal ni nj nk
# outer loop
# vertex v1x v1y v1z
# vertex v2x v2y v2z
# vertex v3x v3y v3z
# endloop
# endfacet
# endsolid name(optional)
while temp = original.gets
next if temp =~ /^\s*$/ or temp.include? 'endsolid' # ignore whitespace
temp.sub! /facet normal/, ''
normal = temp.split(' ').map{ |num| Float.from_sn num }
triCount += 1
temp = original.gets # 'outer loop'
temp = original.gets
vertexA = temp.sub(/vertex/, '').split(' ').map{ |num| Float.from_sn num }
temp = original.gets
vertexB = temp.sub(/vertex/, '').split(' ').map{ |num| Float.from_sn num }
temp = original.gets
vertexC = temp.sub(/vertex/, '').split(' ').map{ |num| Float.from_sn num }
temp = original.gets # 'endsolid'
temp = original.gets # 'endfacet'
outFile.write(normal.pack("FFF"))
outFile.write(vertexA.pack("FFF"))
outFile.write(vertexB.pack("FFF"))
outFile.write(vertexC.pack("FFF"))
outFile.write("\0\0")
end
outFile.seek(80, IO::SEEK_SET)
outFile.write([ triCount ].pack("V"))
outFile.close
else
outFilename = ARGV[0].sub(/\.stl/i, '-ascii.stl')
puts "#{ARGV[0]} is in BINARY format, converting to ASCII: #{outFilename}"
outFile = File.new(outFilename, "w")
outFile.write("solid \n")
# Binary STL format (from Wikipedia):
# UINT8[80] Header
# UINT32 Number of triangles
#
# foreach triangle
# REAL32[3] Normal vector
# REAL32[3] Vertex 1
# REAL32[3] Vertex 2
# REAL32[3] Vertex 3
# UINT16 Attribute byte count
# end
original.seek(80, IO::SEEK_SET)
triCount = original.read(4).unpack('V')[0]
triCount.times do |triNdx|
normal = original.read(12).unpack('FFF')
vertexA = original.read(12).unpack('FFF')
vertexB = original.read(12).unpack('FFF')
vertexC = original.read(12).unpack('FFF')
original.seek(2, IO::SEEK_CUR)
outFile.write(" facet normal #{normal[0].to_sn} #{normal[1].to_sn} #{normal[2].to_sn}\n")
outFile.write(" outer loop\n")
outFile.write(" vertex #{vertexA[0].to_sn} #{vertexA[1].to_sn} #{vertexA[2].to_sn}\n")
outFile.write(" vertex #{vertexB[0].to_sn} #{vertexB[1].to_sn} #{vertexB[2].to_sn}\n")
outFile.write(" vertex #{vertexC[0].to_sn} #{vertexC[1].to_sn} #{vertexC[2].to_sn}\n")
outFile.write(" endloop\n")
outFile.write(" endfacet\n")
end
outFile.write("endsolid \n")
outFile.close
end
original.close
rescue => error
puts "Error: #{error}"
end