Re: A NEW STL FILE FORMAT

From: Evegeny Kotsuba (laser.nictl@g23.relcom.ru)
Date: Thu May 28 1998 - 21:40:30 EEST


Hi,
On Thu, 28 May 1998, CIRTES wrote:
>
> We are looking for some information about a file format for Rapid
> Prototyping more efficient that the STL (without redundancy information
> which can contain topological information). Is there today a STL format
> evolution which is really used ? (VRML ?, RPI?, STEP ?)
>
Some time ago I developed some software for compressing STL, and think
use it's format as default file format for all STL in my project. May be
STP is what you ask about.

This software may be available for OS/2, FreeBSD and DOS+DOS4GW
platforms.

1.0 What it is.

STLPACK.EXE is compressor for STL files
[...]
STLPACK produce STP files from STL.
[...]

2.0 Using STLPACK

STLPACK reduces the size of STLs better than filecompressors,
and more, you can use your favorite compressors for consequent packing
output of STLPACK. For example, you can use it as:

to compress STL file:

STLPACK YourFile.STL YourFile.STP
ZIP YourFile.ZIP YourFile.STP

to decompress STL file:

UNZIP YourFile.ZIP
STLPACK YourFile.STP YourFile.STL

2.1 Table of file sizes:

filename STL STL+zip STP STP+ZIP
-----------------------------------------------------
femur.stl 17828084 7530181 4790012 2606362
CTR data

srt01_v.stl 2523484 1090659 605560
341837
SR1.STL 2521584 1196169 605072 400139
robotb.stl 2360634 709387 578702 287057
kasko_o.stl 2274784 1020121 500418 362134
                                        
BOTTLE STL 685684 267319 149340 66062
CARWHEEL STL 358284 163407 82508 52988
PUMPE STL 314184 90331 69442 39272
CONES STL 7384 2775 1526 1297
----------------------------------------------------
Sum 28845222 12054762 7400354 4178149
Typical medium 41.79% 25.65% 14.48%
Compression Ratio
----------------------------------------------------
3d_stl.stl 35503684 4187468 8404268 2805396
very non-smooth,
made from small
cubes, CTR data.
----------------------------------------------------
Total Sum 64348906 16242230 15804622. 6983545
Medium Ratio 25.2% 24.5% 10.85%

Evgeny Kotsuba

For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/



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