parametric and direct, conversation (i)

[cacciatorino]

on the American forum of if I found a discussion between a user and Mr. John Bakerr, which is defined in the sign "product evangelist" on behalf of siemens-plm. He gave me permission to translate and post it here, which I gladly did because I like history and here he finds some.

As I was translating, I was doubtful that questions and answers were driven to the origin, however, even if I had finished translating a sort of corporate vein, I think it remains interesting for us to cad3d.it.

user:
today I received an email with the following questions for which I have no good answers. I know that some of you have been working in the industry for a long time and you'll probably get the answers.♪
next August are 34 years.
user:
the questions are as follows. Why now direct modeling?
years ago, there were two possibilities of solid modelling:

1. history based

2. direct modeling without historyJB:
This goes back long before the middle of the '90s. the first solid modelers originate from university and government research and development projects, started in the 1970s, and culminated in the first commercial products introduced in the early 1980s, such as geomod, developed and marketed by sdrc (now part of siemens plm), synthamen, fired and marketed by applicon (now part of siemens plm), unisolidc, developed and marketed by m
to be precise, a couple of these (synthavision and unisolids) were technically “history based”, as csg-type systems (constructive solid geometry) which depended on the re-execution of a “diagram” that could exercise edited thus regenerating the model, but they did not make any use of what would in the future be known as parameters, and certainly had nothing similar to mathematical expressions.
in the case of geomod and romulus-d, which were not csg systems, only romulus-d could be considered close to current b-rep modelers (b-rep: boundary-representation). to note that the tools on which it was based romulus-d are then evolved in parasolid, which is the basis of many current cax products, including solid edge and nx, as well as solidworks, ironcad and various others, and that it is at the base, along with d-cubed, another cambridge company today part of siemens plm, of the work that led to the development of proprietary synceus modeling tools
However, what I mean is that the issue “history” versus “direct modeling” has existed for years.

 

[cacciatorino]

user:
what pushed the model “history based” to overcome that “direct modeling”?

1. Was it the power of calculation? Does direct modeling require more powerful cpus?♪
in good part, yes.
one of the limiting factors, especially in the first csg modelers, were the performance of the hardware, not so much in terms of memory, as in absolute speed, as the calculations needed to re-execute a “diagram” could be very heavy (I made my first public demo in the spring of 1982, when I worked for mcauto, with a prototype of what would later become unisolids).
In our case, when unisolids was released (principle of 1983), it basically required all the dedicated 32-bit vax computer resources (filling a small room), to create anything of any complexity.
the improvements continued, and the hardware improved, in turn, so that we brought unisolids on more powerful mainframes, so that we also had a modest success, selling about 600 licenses (at that time, a license enabled a single mainframe to perform all the instances that the resources allowed, that for unisolids meant no more than 2 or 3 processes in execution at the time on the greatest machines).
We were also developing the first rough parametric concepts, although with the use of “programs” written by users, but this allowed a certain amount of “design intent” to be incorporated into the solid model, but they were the hardware resources limiting factor.
user:
2. Was it a pure marketing factor? We all know how aggressive ptc sales policies were at that time.♪
That was the paradigm shift, as we called it later. ptc was the first successful b-rep solid modeler (they were not the first to offer a true parametric modeling system, but only the first to sell and assist it efficiently) that combined the speed and efficiency of the b-rep representation (superfici with defined spatial volumes) and the structure “diagram” of the csg modeling (but without overload for the cpu).

ptc has done more than anyone before them, to push us to improve the products, and it was only their arrogance of big company and their burnt earth tactics that prevented them to have more success, and given to the competition the time to react with competitive products, which in our case led to the release of paraca v7.0 in 1989 that was our first product that included a complete possibility of modeling
to note that we had nothing comparable to a “feature-based” parametric system until 1991 when we released ug v8.0 that had something called ug/concept, which, although based on ugs, was not fully integrated but provided our first sketcher and a system of expersions to parametricly pilot a solid model. This missed up to ug v10.0, released in 1993, where we finally introduced a parametric cax and feature-based system, which could compete head-to-head with pro/e.

user:
3. What has it done that ten years have passed between the fusion between ug and sdrc and the development of the “live rules”?♪
I'm not so sure that we can say that the acquisition of sdrc by ugs (it was not a fusion) led directly to what we call synchronous technology today, since we already had a form of direct modeling, known with the commercial name of dmx (direct modeling extension), present in ug already' from v17.00, which was released in 2000, a year before the acquisition of sdrc. Now we know that even those of i-deas were working on a primitive modeled 3d based on constraints (constraint based), and I'm sure that part of that work has influenced and contributed to what we have today, but the acquisition was not a determining factor as we were already on the way to unravel these skills as part of a complete cax product.
user:
Is it another paradigm shift? I speak of live rules, which fundamentally bind 3d data to surface level?♪
was really the idea of guiding a topological model using a 3d solutor as d-cubed, something that we have in a very rough shape for about 30 years, and in a much more efficient way from about 10, but that was not fully usable until we were able to overcome the limitation of creating and “destroy” ratological elements (spigols, faces, vertices) to the flight during a change and maintain the no
Once we have achieved this through our synchronous technology (and protected by numerous patents), this is the most recent, and perhaps more meaningful, breaking point.
user:
Has something like the “live rules” existed in the past?♪
the ug-dmx features allowed to create 3d bonds that could be edited without requiring the re-execution of the model tree to see its results, but in almost totality of the cases, the resulting model had the same “topological map” (the pattern of faces/spigols/vertical) before the change.
As long as you stay with the same number of vertices/faces/pigols and with the same relationships among them, you can do practically everything with the simple “direct modeling”.

user:
do other systems have something similar to “live rules”?♪
cocreate is the most known, but other systems have similar concepts, such as spaceclaim and, at a lower level, ironcad.
user:
the cad industry produced a new case betamax vs vhs? I mean, the best technology has been expelled from the market?♪
I don't think so.
In fact, the best technology has been here for 30 years, it only needed modern hardware and programming tools to become practical and usable.
I think we got a lot more than we expected, even going back with our minds and imagining what we could do after we exceeded all the gaps and limitations we were facing in our r&d labs.
user:
or the industry of time had a better understanding of the dilemma history vs direct and that made it take so long to fully develop direct modeling?♪
In some respects, as I said before, we wanted the maturity of various “pieces” of technology before there was enough synergy and “critical mass” to make sure that everyone worked as we dreamed many years ago.

for a very part story of what I told, please visit the unigraphics virtual museum:
http://plmworld.org/museum/ Note that some of the former sdrc recently added sdrc history, whose links found at the bottom of the page mentioned at the link.

Moreover, if you want a broader and more independent review of the history of the cad and details about most of the various actors on the market, I suggest the book:
'the engineering design revolution: the people, companies and computer systems that changed forever the practice of engineering', by david e. weisberg, who you can find online at:
http://www.cadhistory.net/ I hope that the above can answer questions and doubts.

 

[Er Presidente]

I never had any doubts, I always fought the epidemic!
:biggrin: