                           freeCAD
                3D CAD with Motion Simulation
                             by
                          A-S Koh
                    curriculum vitae (resume)
                   askoh@alumni.princeton.edu
                     http://www.askoh.com

Page updated: 2002/01/01
'freeCAD5' was created on 2001/12/30.
patch50.zip supersedes all other patch5*.zip.



     What is 'freeCAD'?
     What are the features of 'freeCAD'?
     What is new in this release?
     Are there any reviews or articles?
     Is 'freeCAD' open source?
     How to download, install, patch and 
     quick test 'freeCAD'?
     Are there documentation, tutorials or 
     examples?
     What are the known problems?
     How to uninstall 'freeCAD'?
     Where can I get help with 'freeCAD'?
     What is a sponsor?
     How can I help?
     How to use 'freeCAD'?
     Disclaimer



What is 'freeCAD'?

'freeCAD' is a basic 3D CAD with advanced Motion Simulation capabilities. 
It is suitable for anyone interested in learning 3D CAD and Motion Simulation 
for free before using more sophisticated packages. Educators, students and 
new engineers will find it ideal for the teaching and learning of geometry, 
kinematics, dynamics, vibrations, mechanisms, linkages, cams, machine design 
and physics. The program runs on Windows, Macintosh PPC, Linux PC and 
other Unix's. Assembly data are unchanged across platforms. It is a 
FREEWARE which is sponsor supported. Releases will be made quarterly.

'freeCAD' allows users to create and manipulate assemblies of parts. The 
parts are simple 3D solids, which can be connected by joints, constraints, 
contacts, motors, actuators, springs, dampers, forces, torques or gravity. The 
parts and connections define the structure, mechanism or machine of interest. 
Both open and closed 3D loops are permitted. 'freeCAD' performs full 
Multibody Dynamics analysis on the assembly to predict the motion according 
to Newton's Laws. Animation using the simulated data produces realistic 
dynamic behavior of the system.

Users can study the mechanical dynamics in the form of plots and tabular 
output. XY plots can be zoomed and set to equal scales. Data series available 
include linear and angular displacements, velocities, accelerations, forces, 
torques, momenta and kinetic energies. Acceleration data include transverse, 
centripetal and Coriollis accelerations. Users can view forces and torques 
from joints, constraints, actuators, springs, dampers, applied forces and 
inertia.

 Screen Shot




What are the features of 'freeCAD'?

'freeCAD' is capable of full 3D pan, zoom, tilt and rotate. Available solids are 
extrusions of rectangles, circles, ellipses and polygons. The solids can be 
positioned and oriented exactly in space, as are markers on the solids. Exact 
specification of linear and angular velocities of solids in space are also 
possible. Mass and inertia properties can be user specified or automatically 
computed based on uniform density. Available joints are spherical (ball), 
revolute (pin), translational (slider), cylindrical, planar, fixed, universal, point in 
line, point in plane, parallel, perpendicular, no rotation, constant velocity, rack 
pinion, screw. Both open and closed 3D loops are permitted. The 
curve-curve contact allows liftoffs and collisions based on coefficient of 
restitution. Available actuators are rotational and translational. Their motions 
are user prescribed functions of time. Forces and torques are user prescribed 
functions of time, displacements and velocities in all three components or 
along connecting markers. Example formulas for spring, damper, bushing, 
beam, aerodynamic, inverse square law and other forces and torques are 
given. Users can specify constant gravity of arbitrary magnitude and direction. 
'freeCAD' can compute kinematic, quasi-static or dynamic solutions based on 
the assembly and user requests. 'freeCAD' does redundant constraint removal 
automatically. Simulation progress is animated and the simulation can be 
stopped any time. After simulation, the computed solution can be used for 
animation or frame by frame analysis. Full 3D pan, zoom, tilt and rotate is 
available during simulation and animation. Users can obtain engineering data in 
the form of plots and tabular output. XY plots can be zoomed and set to 
equal scales. Data series available include linear and angular displacements, 
velocities, accelerations, forces, torques, momenta and kinetic energies. 
Acceleration data include transverse, centripetal and Coriollis accelerations. 
Users can view forces and torques from joints, constraints, actuators, springs, 
dampers, applied forces and inertia. Individual parts can be save into files and 
reinserted into any assembly repeatedly. Assemblies can be saved with textual 
notes and simulation data for later reload. 'freeCAD' runs on Windows, 
Macintosh PPC, Linux PC and other Unix's. Assembly data are unchanged 
across platforms.




What is new in this release?

Notes can now be created, viewed, modified and saved with the assembly. 
More views and plane selections are provided. A new sponsor. Click on 
sponsor messages to visit sponsor web sites.




Are there any reviews or articles?

Search for 'freeCAD' at the following web sites:
ZDNet http://www.zdnet.com
CNet http://www.cnet.com
TUCOWS http://www.tucows.com
Simtel http://www.simtel.net
Top Quality Freeware http://www.topqualityfreeware.com
Cad Depot http://www.caddepot.com
             The Internet Resource for Engineering Professionals
Mechanical Engineering magazine, September 2001, "Software Exchange, 
3D-CAD", http://www.asme.org
CADENCE magazine, October 2001, "Analysis Tools For The Desktop", 
http://www.cadenceweb.com




Is 'freeCAD' open source?

'freeCAD' is created with the open source StCAD: 3D CAD Framework for 
Smalltalk and a private motion simulation program. All the source code is in 
Smalltalk which is a pure object oriented programming language. The 
development environment used is VisualWorks which is also open source.




How to download, install, patch and quick 
test 'freeCAD'?

If your internet connect is unreliable, use Download Accelerator Plus to 
resume incomplete downloads.

To try 'freeCAD' in Windows 95/NT or higher with 64MB or more 
RAM:
Create a directory, say, C:\freecad5 for the downloads.
Download freecad5.zip  (4.47MB, 4688811 bytes).
Download patch50.zip  (9KB, 9283 bytes).
For alternative download web sites, go to the reviews section above.
Unzip freecad5.zip into the same directory.
Unzip patch5*.zip into the same directory. Let it overwrite other files.
Double click on freecad5.exe to launch the application.
If double clicking doesn't work, create a shortcut containing the full command 
below:
C:\freecad5\freecad5.exe  C:\freecad5\freecad5.im
The working directory should be C:\freecad5
Then double click the shortcut.
Known Problems

To try 'freeCAD' in Macintosh PowerPC:
Create a folder, say, freecad5 for the downloads.
Download freecad5.zip  (4.47MB, 4688811 bytes).
Download patch50.zip  (9KB, 9283 bytes).
Locate and download PowerMac OS9 virtual machine at 
http://www.cincom.com:80/scripts/smalltalk.exe/downloads/index.asp?content=visualworks
Open Stuffit Expander's preferences dialog to Cross Platform options, and 
select
"Never" for "Convert Text Files to Macintosh text format".
Then for the Destination options, select
"Same as original" for "Destination"
"Never" for "Create Surrounding Folder".
Decompress freecad5.zip into the same folder.
Decompress patch5*.zip into the same folder. Let it overwrite other files.
Decompress virtual machine file into the same folder.
From subfolder freecad5:bin:powermac, move the application visual into 
folder freecad5
In folder freecad5, drag freecad5.im and drop onto visual to launch the 
application.
Alternatively, create a alias containing the full command below:
visual freecad5.im
The working folder should be freecad5
Then double click the alias.
You may delete subfolder freecad5:bin:powermac and its remaining contents.
Known Problems


To try 'freeCAD' in Linux PC:
Create a directory, say, /home/username/freecad5 for the downloads.
Download freecad5.zip  (4.47MB, 4688811 bytes).
Download patch50.zip  (9KB, 9283 bytes).
Locate and download Linux virtual machine at 
http://www.cincom.com:80/scripts/smalltalk.exe/downloads/index.asp?content=visualworks
Decompress freecad5.zip into the same directory.
Decompress patch5*.zip into the same directory. Let it overwrite other files.
Decompress virtual machine file into the same directory.
From subdirectory /home/username/freecad5/bin/linux86, move the 
executable visual into directory /home/username/freecad5
Repeat for file herald.so.
Change directory to /home/username/freecad5
In a terminal window, execute: ./visual freecad5.im
Alternatively, create a script containing the full command below:
/home/username/freecad5/visual  /home/username/freecad5/freecad5.im
The working directory should be /home/username/freecad5
Then double click the script.
You may delete subdirectory /home/username/freecad5/bin/linux86 and its 
remaining contents.
Known Problems

To try 'freeCAD' in other Unix's:
Follow instructions for Linux PC.
Locate and download your virtual machine at 
http://www.cincom.com:80/scripts/smalltalk.exe/downloads/index.asp?content=visualworks



Version check:
Since 'freeCAD' can be downloaded from many locations, it is good to check 
that you have the latest version.
Inside 'freeCAD', click Explain/About/freeCAD/ to locate the creation date:
'freeCADx' was created on yyyy/mm/dd.
Verify that you have the latest copy by comparing with the creation date 
published at:
http://www.askoh.com
Also check that your have the latest patch for the version.

Quick test 'freeCAD':
Click File/Open/Assembly/ to get a list of example assemblies.
Choose one, say, fourbar.asm
Click View/Tilt Rotate/ to center the model.  Drag the handles to tilt and 
rotate the 3D assembly.
If necessary, Click Edit/Marker Size/ to set marker sizes suitable for the 
drawing.
Click Simulation/Animation/ to get the animation dialog. Click Play to start 
animation.
You can click any View menu item and drag the tilt and rotate handles, even 
during animation.
Close animation window when done.
Please report problems to
A-S Koh
askoh@alumni.princeton.edu

Quick start:
Click Explain/Quick Start/ to learn how to build a model from scratch. 
Together, the tutorials demonstrate the available features in 'freeCAD'.




Are there documentation, tutorials or 
examples?

Documentation are inside the program. They are collected in a series of menu 
items labeled 'Explain'. Click on them anytime. Inside 'freeCAD', click 
Explain/Quick Start/ for a list of tutorials on projectiles, circular motion, 
relative motion, pendulums, spring-masses, four bar linkages, piston crank, 
gyro, cam follower.

The motion simulation theory is in the journal paper:
Koh, A-S., and Park, J-P. "Object Oriented Dynamics Simulator," 
Computational Mechanics, Jun 1994, 14(3) 277287.

More Example Assemblies




What are the known problems?

Please report any problems. Let me know if you can make the installation 
process easier.

All Platforms:
If an error message comes up, click on "Continue" to let Smalltalk recover. 
You can usually continue if you avoid the offending steps. Every error is 
logged in a file called error.log. Email that file to the author for debugging. 
Patches and workarounds will be posted as soon as possible. Thank you in 
advance.
'Invalid zip file'. Check that the download files have the exact number of bytes 
shown above.
On Windows:
Right clicking on some mice does not bring up the correct menu. Try right 
clicking while holding the ctrl key down.
On Windows 98, the help dialog for motion and force-torque dialogs will not 
close when the X button is clicked. Close with ESC key.
On machines with low memory, desktop icons may become white when 
'freeCAD' exits. Reboot to recover. Internet Explorer 5.5 seems to be the 
cause. Upgrade to Internet Explorer 6.
On Linux:
'Out of Memory' error at startup. The probable cause is having too many 
fonts. Execute with the following command to start freeCAD
./visual -h10M freecad5.im

Please report problems to
A-S Koh
askoh@alumni.princeton.edu




How to uninstall 'freeCAD'?

To uninstall, just delete the freecad* directory and its contents. 'freeCAD' 
does not change any settings on the computer.




Where can I get help with 'freeCAD'?

For the latest information, freeware downloads, patches, examples and open 
source of 'freeCAD', visit:
http://www.askoh.com

To pose a question for general viewing, submit it to the newsgroup alt.cad. 
Prefix the question with [freeCAD] to distinguish it from other questions on 
different topics.

You can email your questions to:
A-S Koh
askoh@alumni.princeton.edu




What is a sponsor?

'freeCAD' is a freeware suitable for anyone interested in learning 3D CAD 
and Motion Simulation for free before using more sophisticated packages. 
Educators, students and new engineers will find it ideal for the teaching and 
learning of geometry, kinematics, dynamics, vibrations, mechanisms, linkages, 
cams, machine design and physics. Since its release in July 2000, 'freeCAD' 
has been downloaded at least 70,000 times. For proof, search for 'freeCAD' 
at the web sites mentioned in the reviews section. The master website 
(http://www.askoh.com) receives 200 unique clients who download 500MBs 
daily. Since 'freeCAD' is freeware, it can be downloaded from many sites that 
are not accounted for in the above numbers. A search for 'freeCAD' on any 
major search engine will point to about 100 relevant links worldwide.

Sponsors can advertise on the 'freeCAD' web site and inside the 
'freeCAD' program to promote their products, services, publications 
and job opportunities. There will be no more than ten advertisers inside the 
program at any one time. Each advertiser gets equal time to show his/her 
messages at various points (title bar, menu item, dialog boxes, status bar) in 
the program as the users use the program. Advertisers can change their 
messages every quarter when new releases of 'freeCAD' are made. For the 
price of US$500 per month, sponsors can advertise to over 5000 new users 
of 'freeCAD' per month. In addition, continuing users of 'freeCAD' will still 
see their advertisements.

Sponsors can also request for customizations of 'freeCAD' and other 
consultancy services from the author. A-S Koh's curriculum vitae (resume)

For more information, please contact A-S Koh at (505) 661-9779 or 
askoh@alumni.princeton.edu




How can I help?

Your bug reports and suggestions are most valuable for improvements in 
'freeCAD'. If you have example assemblies to share so that others can benefit 
from your work, please let me and others know about them. I can include 
them on this site if you want. If you like programming, I welcome you to look 
at the open source and discover the wonders of pure object oriented 
programming and the productivity gains that can be had. Finally, but not least, 
please tell your friends and colleagues about 'freeCAD'. Thank you very much 
for your contributions.




Disclaimer

'freeCAD' is provided 'AS-IS' with no warranty as to its use or performance. 
By using it, you agree to indemnify the author from any liabilities that you may 
incur from the use of the software.


Copyright (C) 2000-2002, A-S Koh, All Rights Reserved.

