Paul Tyson wrote: (01)
> I don't know the history of computer graphics
> applications, but something similar must have happened--the early
> developers looked at draftsmen putting lines and curves on mylar and
> decided to write a program to put lines and curves on a CRT. It's taken
>several
> generations of graphics software (each having to "interoperate" with the
> previous generation) to really begin to augment the engineer's primary goal
> of communicating design intent--and some people still don't believe that's
> possible without honoring the conventions of antique draftsmanship. (02)
Well, part of the problem was to get an effective computational representation
of solid geometry, and the tools that did that began to emerge after academic
feasibility demonstrations in the mid 1980s. And part of that feasibility was
having fast enough processors, accurate arithmetic, and fine enough graphical
resolution and fast enough graphics refresh. That is, a mere 4 or 5
technologies were needed to enable that. (03)
BTW, putting accurate lines and curves on a CRT from a digital source, rather
than an analog recording, was no small feat in 1970, when the early graphical
CRTs first appeared (at significant cost). As late as 1990 the cost of top of
the line graphics terminals was in the 30K$ range, and had been since the first
ones 20 years earlier, which is a big difference in constant dollars, and had a
big impact on the size of the potential market. The Tektronix folk made the
price/performance breakthrough about 1974, and dominated the market for 10
years until cheap raster technology emerged that could approximate the accuracy
of their technology. (04)
And for the record, the antique draftsmanship conventions have a different
motivation -- long-term archival of the engineering models. What CAD form from
1985 can still be processed? Do you think all those 1985 aircraft have been
junked? Do refineries built in the 1980s still function? If we now commit to
saving the latest and greatest Pro-Engineer solid models in native form, what
tools will be able to read the recording media and decode the model and display
the holographic images in 2025, let alone 2050? If you are authorizing the
construction of a nuclear plant, what archival form of the engineering models
are you going to require? Maybe those antique draftsmen still have a value. (05)
I agree with Paul's sentiment, but the business of engineering models is
important, it is very high tech, and it is fraught with all kinds of very real
business constraints. (06)
-Ed (07)
--
Edward J. Barkmeyer Email: edbark@xxxxxxxx
National Institute of Standards & Technology
Systems Integration Division
100 Bureau Drive, Stop 8263 Work: +1 301-975-3528
Gaithersburg, MD 20899-8263 Mobile: +1 240-672-5800 (08)
"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority." (09)
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