Niels Horn's Blog

CAD Programs on Slackware - 1

April 24th, 2010 by Niels Horn in CAD, Slackware

History

Many years ago (talking about the mid/late 80s) I worked at a company that used AutoCAD for 2D construction designing. This was done on Sun Graphical Workstations that were networked together using a Thick Ethernet coaxial cable and a Unix file and print server. I learned a lot about shell scripting, network configuration, lpr / lpd printing, access permissions, terminal configurations, etc.
I didn't understand much of what the architects and engineers designed, as I was more interested in the technology behind it all. But I remember that the whole IT setup was expensive: software licensing, specialized hardware (off-the-shelf Intel boxes couldn't do yet what Sun could at the time), highly skilled network administrators (I was only a junior at the time), etc.
After a while, I changed jobs and moved into the financial administration business, where I learned other skills, many of which I still use on a daily basis…

Recently I regained interest in CAD programs, as a relative asked me to take a look at two files he received at his company that he was unable to open. It turned out that they were created by specialized 3D modeling software that costs thousands of dollars and runs only on Windows (he uses Slackware, of course!).
For someone who needs to open a file like that maybe once or twice a year, it's not a wise investment.

So I started looking around for cheaper (preferably free) software that could open these files and display them on Slackware. It turned out that the formats used for those files were closed and exclusive, but those commercial programs can save their files in some open standards, like STEP or IGES. So my quest for a working, cheap/free CAD system for Slackware had started!

2D vs. 3D

Back when I worked supporting AutoCAD, all that was done was 2D designing: buildings, floor plans, etc. There were "layers" in the designs, but nothing was visualized in 3D. Even the expensive Sun Workstations did not have the graphical capabilities needed for that. But things have changed and nowadays, even reasonably priced desktop systems - with a modern graphics card - can do impressive 3D modeling using the right software.
Some programs are specialized in 2D designing, others in 3D, some can do both very well.
To clarify the difference between 2D designing and 3D modeling, here is a simple example of both (both images were created with the trial version of VariCAD):

This image is a drawing of a simple piece in 2D

And this is the same piece modeled in 3D

Selected programs

So I wanted a program than can match the following requirements:

• Works or can be made to work on Slackware Linux
• Is free or affordable (meaning not in the $thousands range)
• Can read some of the open formats like STEP or IGES
• Ideally does both 2D & 3D, but if it's really good at one of the two, or is really cheap (or free), I'll consider it as well

After some initial research, I decided to check out the following programs:

1. VariCAD: Commercial software, but seems to be very complete (2D + 3D) and has a fully supported Linux version
2. FreeCAD: Free, open source, 3D, can read IGES & STEP, but seems to be a work-in-progress
3. BRLCAD: Free, open source, 3D, created by the US Army for designing tanks, can read IGES
4. QCAD: Commercial (but less then $50,00) + limited free "community" edition, 2D only

My findings about each program will be published in future posts on this blog.
If I can get a program to work on Slackware, I'll submit the SlackBuild script to SlackBuilds.org, so that it becomes available for everyone to try out.