Here are a few links I've saved that might be interesting to you or give you some leads and/or insight:

AR-CAD
<http://www.ar-cad.com/index.html>

FREECAD
<http://www.oopgames.com/freecad/>

StCAD
<http://www.ar-cad.com/stcad.html>

Dr. Geo II
<http://documentation.ofset.org/drgeo/videos/drgeo2-center.mpeg>

Géométrie Interactive Enrichie Et Mosaïque
<http://people.ofset.org/hilaire/drgeo2/demos/4-mosaique/index.html>

ODE - Open Dynamics Engine
<http://g-24.net/squeak/ode.html>
<http://languagegame.org:8080/ggame/15>

UIDesigner
<https://www.hpi.uni-potsdam.de/hirschfeld/trac/SqueakCommunityProjects>
<https://www.hpi.uni-potsdam.de/hirschfeld/trac/SqueakCommunityProjects/wiki>

Thinglab
<http://wiki.squeak.org/squeak/607>

I'm an EE so look forward to following your work.
Good wishes.
  
   Ken G. Brown

At 1:07 AM +0800 2/25/11, lists.squeakfoundation.org at ben.coman.com.au apparently wrote:
>greetings all,
>
>To introduce myself, I first experienced Smalltalk around 1990 as part of my undergrad in IT Engineering.  It made a great impression on me but unfortunately I never got a chance to use it professionally, and hadn't touched it since.  I then worked fifteen years in IT doing desktop/server/network support of windows/unix/linux systems.  My career got a bit stale so the past five years I have been doing external postgrad study at the University of Southern Queensland for a MEngTech Power Systems.  The past four years I've been working for a small Electrical Engineering & Contracting firm doing industrial control and power systems.
>
>My Final Project & Dissertation is now upon me and I've decided to develop an engineering design tool.  The discovery of Squeak a few weeks ago and then working through Squeak by Example and the Laser Tutorial was a major influence in choosing to undertake this project.  Part of it is a schematic and connection drawing package where changes are live linked between associated drawings. For example, when wire numbers are changed on the schematic that will be reflected on the connection diagram.
>So now I need to evaluate and choose a framework.  So far the options I see are:
>
>1. Pure Morphic - might has the advantage of being well supported with examples.   I can already imagine how things might be implemented - including maintaining vertical-or-horizontal-only orientations while moving wires around. It is more likely that unintended behavior can be understood and prevented.  The model coupling is also well demonstrated in examples.
>
>2. Ned Konz's Connectors  - I have been playing with Ned Konz's Connectors framework this week and am quite excited by its potential.  However I wonder how well it integrates with an underlying model to maintain consistency across multiple views.
>
>3. GraphViz - seems to be less interactive than Connectors providing mainly graph auto-generation - though I haven't tried it yet.
>
>4. Mondrian - seems to be less interactive than Connectors providing mainly graph auto-generation - though I haven't tried it yet.
>
>5. Cobalt, for later addition of 3D equipment layouts and cable routing.   I could only spend a few hours with it.
>
>In general, the more developed frameworks should provide more sophisticated features "for free", but the trade offs are time-to-learn, framework maturity, susceptibility to framework bugs, potential complexity to trouble-shoot framework internals.  Also there may end up a mismatch between requirements and framework possibilities, and being able to extend them.  There also doesn't seem to be a great deal of consolidated documentation for each framework.  So trying to understand the high level design and usage philosophy by wading through low-level code is awkward.
>
>I am interested in your opinion on the choice of suitable frameworks? Did I miss any?
>
>The basic model will be composed of:
>a. Drawings - A3 size with standard client borders. A large electrical project may have thousands of drawings.
>b. Components - with terminals to which wires connect.  These will be developed custom by the user.  Components have Subparts that scatter around a drawing.  For example a relay has an input-coil and an output-contact that appear in different parts of the circuit. .  Component Subparts Components will have various graphical representations depending on which type of drawing they are on.
>c. Wires - which inter-connect component terminals.  All short-circuit-connected wires should have the same wire number. d. Cables - contain multiple wires to connect between drawings and physical locations.
>e. Voltages and currents on components and in wires.
>
>Design rule checking (such as preventing mixed voltages) will be done against the model.  The schematic will be simulated to observe the effect of push buttons and relay logic.
>cheers, Ben