STLPACK vers. 0.33

(c)Evgeny Kotsuba 1997-1999

What it is.

STLPACK is multiplatform compressor for STL files, de-facto standard for Rapid Prototyping systems. (Laser Stereolithography Apparatus is most known Rapid Prototyping technology and STL stands for STereoLithography)

Why it may be needed.

STL format is very simple and well suited for RP applications but there is one problem: STL files have very big size. Even in binary form. Typical size for mechanical models is 0.2-2Mb, for medical applications (RP copy of computer tomograph images) -- 5-50Mb. If you want to transfer such files via Internet with modem bps even 2kb/sec, this problem becomes PROBLEM.
On the other hand, if you maintain archive of STL models then you also sometime will face with that problem. Usual compression reduces size of STL, but problem remains.


This software is shareware.
You can use it for free for evaluation purposes only till 1 of April of 1999.
After 1 of April 1999 you should register your copy of STLPACK or delete it from your computer(s).
You cannot delete author information; you cannot change exe file, do reverse engineering, etc.

STLPACK made in Russia

from natural components... ;-)


STLPACK is text mode application for IBM PC.
OS Distribution file Comment
DOS STLPACKD.ZIP  Need DOS4GW Dos extender
OS/2 (vers. 3,4,5) STLPACK2.ZIP vers.034
Windows 95/98/NT STLPACKW.ZIP Text mode (console) application !


STLPACK reduces the size of STLs better than file compressors, 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:

To decompress STL file:
I recommend to use RAR 2.0 or any from Zip family.

In Windows95/98/NT for better performance I recommend to use STLPACK from "rulez" file commanders, i.e., FC, Far, VC.

Memory requirements.
While compressing, STLPACK uses memory about twice more than binary STL file size.
While decompressing STLPACK uses more than binary STL filesize.

STLPACK can read text STL file, but decompress STP only to binary STL.

STLPACK test STL file for some errors. In case of non-fatal errors it prints info on these errors.

After creating STP file STLPACK always read STP, decompress it in memory and compare it with source STL.
Usual error is the normal's difference, normally such errors occur from degenerated facet.
In case of severe error STLPAK print something like:

[1234]Vertex[1][0] Diff = 1.234
source stl1.f[1234].iVertex[0]=567
target  stl2.f[1234].iVertex[0]=789
In this case please E-mail me bugreport with rar'ed or zip'ed source STL.
If total size of bug rar/zip will be more than 1 Mb, please split it in parts;
Don't mail me if total size is more than 10 Mb (this is my mail box size at my provider)

Table of test file sizes:

CTR data
17828084 7537791 7321134 4367010 2250182 2149771
srt01_v.stl 2523484 1090787 1059437 524492 331962 325661
SR1.STL 2521584 1196169 1067850 556901 385387 366677
robotb.stl 2360634 708608 594366 524765 265591 242009
kasko_o.stl 2274784 1020121 996673 454742 337709 332733
BOTTLE.STL 685684 267319 250833 134759 65360 62404
CARWHEEL.STL 358284 108589 99417 74085 49263 47203
PUMPE.STL 314184 90467 86186 62956 32707 32065
CONES.STL 7384 2820 2740 1483 1272 1223
Sum 28845222 12022671 11478636 6701193 3719433 3559746
Typical medium 
Compression Ratio
100% 41.79% 39.79% 23.23% 12.89% 12.34%
very non-smooth, 
made from small 
cubes, CTR data.
35503684 4187486 3903403 7427921 2376237 1878741
Total Sum 64,348,906 16,210,157 15,382,039 14,129,114 6,095,670 5,438,487
Medium Compression Ratio 100% 25.19% 23.90% 21.95% 9.47% 8.45%

Author info:

Evgeny Kotsuba
laser. nictl @ g23. relcom .ru (Sorry, there is no mail link for anti-spam protection)

Laser Receach Center (IPLIT RAN, former NICTL RAN) homepage 

Page was updated: 21 Mar 1999