12.3 SYSTEMS WITH "'HIGH OVERHEAD"THE NEXT GROUP OF PRODUCTS...

3.12.3

Systems

with

"'High

Overhead"

The next group of products have been built to do high-end solid modeling with real-

time rendering,

and

they maintain a parametric model of the emerging design. This

means that objects are initially created generically without specific dimensions.

When objects are specifically instantiated, dimensions are added and everything

scales up or down to suit. The user is able to define constraints between different

parts of an object and then scale them.

For long-term company growth over several product variants this has enor-

mous appeal. However, there is a major drawback. There is a huge learning time for

such systems. Also, since they are updated every 18 months or so, further retraining

on new "revs" is likely.

These are powerful design tools for a large automobile company or a national

laboratory. In these environments, many similar components in a family are being

designed. Their use in a bearing-manufacturing

company like TImken Inc. is perhaps

the easiest to visualize. Bore sizes, races, cover plates, and the like, can be created

once and then "scaled up or down." For future revisions of a component, any existing

parametric designs that might reside in a software library can quickly be reinstanti-

ated to create a new object in the same family.

These larger systems also have direct links to supplementary packages that

will do

DFM/A

and finite-element analysis. Most of them also include a CORBA-

based open architecture that allows linking to other software applications (e.g.,

SDRC, 1996).

• ProEngineer commercially available from <https://traloihay.net;

• IDEAS commercially available from <https://traloihay.net;

• Unigraphics commercially available from <https://traloihay.net;

• CATIA commercially available from <https://traloihay.net;

Translations between these different commercial CAD systems were once done with

initial graphics exchange system (IGES) and can now be done with product defini-

tion exchange system (PDES/STEP).

PDESISTEP

is evolving into a useful world-

wide standard (see ISU, lY/:iY,lYY3).

Other products such as Spatial Technology's ACIS (ACIS, 1993) play an inter-

mediate role compared with the aforementioned applications. They have specialized

in the "market niche" of creating an open de facto standard for solid representations.

This is finding adoptions in other systems, including AutoCAD. The openness of

ACIS is popular with the research community. From a management of technology

viewpoint this direction toward open CAD systems is important.