Page 37 - MetalForming August 2014

Handling Design Changes
If on the other hand the designer works with non-native data and the business demands excessive data exchange between varieties of CAD tools, then direct modeling can become a significant tool in the CAD toolbox. A quick and easy metric to consider: the amount of geometry being recreated, either manually or automatically, as a result of design changes or next-gen- eration designs. Direct modeling pro- vides an opportunity to greatly reduce the amount of geometry that gets recre- ated, allowing the designer to leverage and reuse geometry in ways that pre- viously were not possible.
While some may consider history- free direct modeling as a lower-level design tool suited only for quick and dirty geometry creation, some mature direct-modeling systems will create geometry at a very high level of accu- racy and quality. After all, in direct modeling, geometry is the master rather than a feature tree. To work effec- tively, the geometry must be robust and accurate. Also, mature history-free direct modeling can allow designers to add parameters, relationships and con- straints to geometry, even STEP and IGES geometry.
Here are seven factors driving the growing use of history-free direct mod- eling:
1) One-off design, where front load- ing a design with robust design intent and structure does not yield long-term value;
2) Where speed is more critical than highly parameterized and structured models;
3) When designers must work with non-native CAD data and interoper- ability ;
4) Where unpredictable late-stage changes occur often;
5) Where product lifecycles are short, i.e.; little payoff for the invest- ment in the structured/ordered model;
6) Where many iterations are need- ed to make critical design decisions; and
7) When stampers need to get parts out the door as quickly as possible. MF
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