Let’s take a look at the features Electric offers as well as the installation and basic usage of the tool.

Features

• Design rule checking
• Electrical rule checking
• Simulation and simulation interface (many options)
• Generation (ROMs, PLAs, Pad Frames, etc.)
• Compaction
• Routing
• VHDL compilation
• Silicon compilation
• Network consistency checking (LVS)
• Logical Effort analysis
• Project Management

Not a bad feature-set for a piece of free CAD software.

Design types

• MOS (many CMOS and nMOS variations)
• Bipolar and BiCMOS
• Schematics and printed circuits
• Digital filters, Temporal logic
• Artwork

Supported file formats

• CIF I/O
• GDS I/O
• EDIF I/O
• DXF I/O
• SUE Input
• VHDL I/O
• Verilog Output
• EAGLE, PADS, and ECAD Output
• PostScript, HPGL, and PNG output

Available platforms

• UNIX
• Macintosh
• Windows

Installation

I will demonstrate the installation on the Ubuntu distribution. This is quite simple, just follow these steps:

1. Open up the Ubuntu Software Center.
2. Search for “electric” (no quotes).
3. Click the Install button.
4. Type your sudo password and hit Enter.
5. Let the installation finish.

Upon completing the installation you will find a new sub-menu in your Applications menu – Education. In this menu you can click the Electric entry to start the program.

Usage

Figure 1

Obviously you need to be familiar with the science and art of electrical engineering to make full use of this application. But even a newbie can tell this tool has a lot to offer. Figure 1 shows the basic Electric window. The largest pane is your working pane and displays your drawing one cell at a time. To move cells you click the right or left pointing arrows in the tool bar (hover your mouse and you will which ones thanks to a tool tip).

The left pane you have the elements necessary to create your drawings. To add an element you double-click and drag it to the the working pane.

Figure 2

One very nice feature (that is not highlighted) is the ability to measure from element to element within a cell. To do this place your elements in the cell and then click on the Toggle Measuring Distance button. When you do this your cursor will change and you can then click on one object and drag your mouse to the next to see a very precise measurement for that distance.

From the list of elements you will find most of the standards such as: Transistors, resistors, grounds, power, Capacitor, Global-Signal, Inductor, And, Or, Buffer, and much more.

Final thoughts

I believe Electric will satisfy any electrical engineer looking for a free, open source solution for their electrical schematic needs.

Believe it or not, there are a number of CAD applications for Linux. Some of those applications are far too basic for the professional-level CAD user. Some, however, are just as feature-rich and complex as the insustry standard AutoCAD. So hopefully, within this article, you will find a CAD application that will meet your needs.

So, let’s get our Linux CAD on!

Installing

All of the software listed below can be installed on Ubuntu Linux by following these steps:

1. Open up the Add/Remove Software utility
2. Search for “CAD” (no quotes)
3. Select the software you want to install
4. Click Apply

QCaD

QCaD is a powerful 2D CAD application that began in 1999 as a fragmentation of another application (CAM system for engraving and LASER cutting). QCaD includes DFX standard file format and supports HPGL format. QCaD’s biggest advantage over many other CAD applications is its ease of use. Most CAD applications are overly complex. QCaD, on the other hand, has a user interface that is clean and easy to use.  QCaD features:

• Layers
• 

  Figure 1

  Blocks

• 35 included CAD fonts
• Metric and Imperial unit support
• Print to scale
• 40 Construction tools
• 20 Modification tools
• Construct/Modify points, lines, arcs, circles, ellipses, splines, polylines, texts, dimensions, hatches, fills, raster images
• Entity selection tools
• Object snaps
• Measuring tools
• 4800 parts library
• Scripting interface
• and much more

QCaD is modular with extensibility being its focus. As you can see, in Figure 1, the interface is very well thought out and easy to use.

Misfit Model 3D

Misfit Model 3D is an OpenGL-based 3D modeling application for Linux that uses triangular-based models. Misfit features:

• 

  Figure 2

  Multi-level undo

• Skeletal animations
• Simple texturing
• Batch processing (via command line)
• Plugin system for adding new model and image filters
• Create rectangles, cubes, ellipsoids, cylinders
• Translation, rotation, scaling, and shearing
• Multiple skins for models
• Frame animations
• and much more

Misfit does not have the best support available and doesn’t seem to support the largest amount of file formats.

SagCAD

Figure 3

SagCAD is another 2D designer for Linux. Upon opening SagCAD, your first thought will most likely be “Whoa, where do I begin?” SagCAD was not created for the inexperienced user. With SagCAD the interface is filled with clickable buttons and no menus. Unless you are familiar with CAD you will look on at the array of buttons and finally have to mouse over each button to know what it does. And to make matters worse, all support is in Japanese! Does this make SagCAD a bust? Only the well-versed CAD user will be able to tell. The good news for SagCAD users is that it is has been around for some time and is still developed and supported. Just make su

Wings 3D

Figure 4

Wings 3D is a 3 dimensional subdivision modeller that has outstanding support and features.  Wings 3D is available for Linux, OS X, and Windows and features support for numerous import/export formats. Wings 3D has yet to reach version 1 so it is very much in beta. But that does not mean Wings 3D is not already quite usable. Take a look at the small gallery of images created by Wings 3D.

Wings 3D offers a users manual and tutorials for those who aren’t sure where to begin.

Blender

Blender is probably one of the most popular of all the CAD applications for Linux. Blender features:

• A revolutionary UI
• 

  Figure 5

  Rigging

• Modeling
• Rendering
• Animation
• UV Unwrapping
• Shading
• Physics and particles
• Imaging and compositing
• Realtime 3D game creation
• Numerous file format support
• Multiple platform support

If you take a look at the Blender Gallery you will see many reasons why Blender is on of the most popular CAD applications in Linux. I should make mention, however, that Blender does not work well in Linux when full desktop effects are turned on. There are issues with the UI and unless you turn off desktop effects, you will have a lot of trouble using Blender.

Final thoughts

Let the tests begin. I have listed five different CAD programs, each of which serves a different purpose. I would like those of you with CAD experience to test them out and see if any of them meet your needs. Does Linux have a decent CAD application? The answer lies in your hands.