 | |
Solid Modeling Database Issues: Good Practices  Don
LaCourse, 3DCADTips.com
Don Meagher, Octree Corporation
December 6, 2004
reprinted by permission from
Often forgotten and under evaluated, the 3D CAD database is the key that
can either unlock system performance or lock your system up! These tips will
help you understand, evaluate and apply good database practices.
-
Understanding and Evaluation
When evaluating solid modeling systems first determine your needs.
Certain database structures are better suited for specific applications.
For example, a faceted modeler is not well suited for output to
machining or NC operations because they do not precisely define
surfaces. However, a faceted modeler can be faster and allow you to work
dynamically with the model shaded. So, determine if you need accurate
surface representation for CAM output or perhaps good visual
representation for product esthetics. Once you determine your needs then
you can more effectively evaluate different systems.
-
Processing & Performance
When dealing with operations where processing time grows faster than
object complexity, a strategy to enhance performance is to minimize the
size and interaction of objects. It is usually desirable to break a
design into as many separate pieces as is practical and to operate on
them in isolation for as long as possible.
-
Solid Modeling and Databases
Designers are sometimes surprised when they cannot directly access their
models in the database. If CAD models are needed for uses not supported
by the CAD vendor, clearly understand your ability to read from and
write to a database using an external program before making a purchase
commitment.
-
Newer Vs. Older Solid Modeling Systems
Newer, more sophisticated solid modeling systems usually incorporate
advanced capabilities (e.g., sophisticated sculptured surfaces) but they
also tend to be less reliable and more difficult to use than more mature
systems. If your situation does not require all the latest capabilities,
it may be desirable to consider a more mature system.
-
Failure Logs
Always monitor reliability in your environment. A log should be kept,
including details of the operations being undertaken at the time of a
failure. Be sure to record all error messages. Isolate failures that can
be traced to system problems (lack of swap space, disk full error,
etc.). Look for failure patterns (i.e., unusual geometric situations
being attempted). Report unresolved problems to your vendor and ask if
such errors have occurred elsewhere (usually they have) and what steps
are being taken to correct them.
-
Vendor Bulletins
Designate someone in your organization to maintain and review all vendor
bulletins, especially those related to reliability. Often fixes or
workarounds have been developed.
About the Authors Don Meagher is a pioneer of volumetric
visualization and the inventor of the "octree" database structure. He
founded Octree Corporation, which provides 3D technology solutions to GE and
other companies.
Don LaCourse is Editor and Founder of
3DCADTips.com, Principal Partner of eDocHelp,
and Contributing Editor for Cadalyst Magazine. Don has over 25 years of
experience in design, documentation and writing about CAD/CAM/CAE issues.
3DCADTips.com is a free, independent and objective information resource for
3D CAD users, administrators, and managers developed exclusively by eDocHelp
and in partnership with Cadalyst Magazine, TenLinks.com and many other 3D
CAD sites.
Its goal is simple but challenging - to continuously provide a wide range of
valuable tips on 3D CAD, CAM and CAE and to bring all application tips on
the web under one roof where they can be contents, indexed, searched and
browsed by you.
More Select MCAD Articles
|
