Carl,

On Dec 22, 3:38 pm, Don Foreman wrote:
On Sat, 22 Dec 2007 13:48:32 -0800, "Carl McIver"

wrote:
So my lab has an EE who uses his own software to work out his own
circuit boards, and I have nothing to draw out all the external interface
and control systems I design and build. A decision was made to find a
single software that he could use for circuit design and analysis, and for
which we could use outside the circuit board.
Why? Would this be preferable to two programs that each does it's
task efficiently and well? You need only pay for software once, but
you pay for inefficiency and difficulty of use every day.

I do a fair amount of packaging electronics for our research work -
sometimes more MacGyver than Maytag, but we make sure our stuff is safe,
and some of it is pretty slick (thanks in large part to help from this
group!). If your EE is using anything like what I am envisioning, I
would not expect it to solve what I imagine your task to be: physical
integration of gizmos on panels and elsewhere in a box to a populated
board with circuit analysis and physical layout spit out by the EE's
software. Am I at all warm??

I typically work with either purchased boards such as screw terminal
boards, packaged transducers, PC/104 computer components, etc., or very
simple home-grown perf boards with soldered jumpers (don't laugh - they
workg). From a physical design standpoint, they become plates with
known hole locations and (when space is tight) varying thickness. I use
QCad to draw all relevant parts of an assembly, and create dimension
layers that guide my milling. It is not "easy" but it works. I create
one layer per view per component - systematic naming is critical to
sanity. To that, add one or two (maybe three) dimension layers per
component. My biggest complaint is that QCad does not anticipate the
range in sizes, which can vary by a factor of ten or more. A reasonable
text size for a 0.5x0.5x3.0" inch bracket is much too small for labeling
a drawing of a 1x2x3 ft "box" for the instrument. I get around the
hassles. I have not used AutoCAD in a long time; it stuck me as bloated
then, but a good 3D system could have some advantages.

On the other extreme, I sometimes use Squeak (www.squeak.org) Smalltalk
to create 3D models using its Alice clone. I used it to create a *VERY*
crude way to "fly" around a model of a shelved cart with discrete
boxes. I was solving a political problem more than a
scientific/engineering one, and needed to be damn sure some things would
fit on a particular cart. I had not yet discovered QCad, and frankly,
the visualization was helpful. I have used the same trick a few more
times. Squeak is free and I will gladly set you up with a framework and
some examples, but there is just so much I can do to teach programming.
If you have some programming experience, you might want to take a
look. A more mainstream alternative would be POV-Ray
(http://www.povray.org/) or perhaps Blender. All three are (AFAIK)
limited to visualization. CAD (of course) offers the opportunity to
create layers with dimensions and machining instructions. QCad will not
offer the fly-around views, but what do you expect for $35? I find it
worth every penny BTW.

Good luck!

Bill