Parametric AND Direct

By MarkBurhop

A few weeks ago I watched the Parametric versus Direct Smackdown between a number of CAD vendors (including our own Dan Staples).  We are also seeing more of the CAD companies put out more information and videos around this subject.

The interesting part of this debate is there really is no more debate.  Everyone that participated basically said both are important and both offer advantages depending on the problem you are solving.  As a CAD designer, you want both tools in your toolbox, pulling out the screw driver when you need a screwdriver and the hammer when you need a hammer.  Maybe, in a few cases, you only ever need a hammer but who knows what is coming down the road. If I was buying some expensive CAD software, I’d like to keep my options open.

OK, so as a new CAD customer, I basically just need to go to a company that supports both or maybe pick one “direct” and one “parametric” product from two vendors, right?  Well, it’s more complicated than that and part of my reason for writing this post today. For example:

  • There is no reason a “direct” editing tool can’t support parametrics. In fact, most are. “Direct” may be history free (by some definitions) but it doesn’t have to be parametrics free. (and for Pete’s sake marketing people, look up the definition of the word “parametric”.Parametric > History ).

  • Are you going to have to pay twice, once for the history based parametric tool, once for the direct tool?

  • Can the direct solution support the concept of features (and I don’t just mean face sets). Sometimes a hole is just a cylindrical cutout and sometimes a hole is a hole.

  • Are you going to have to learn two different user interfaces?

  • At what level can you mix history-based and history-free technologies? In the end, does it all have to be history based? Can you just mix them at the assembly level?  Can you mix them at the individual part level?

  • Can you use the direct editing tools and the Assembly level? Can you use parametrics at the assembly level to maintain relationships between parts?

  • What is the history of your history-free direct modeler?  Is it being used in production? Does it have a track record? What customers are using it every day for real work?

OK, obviously, I’m a Solid Edge Synchronous Technology guy and we have good answers to all these questions. My hope is to raise awareness, not market but they sometimes look the same…sigh. If you really hate it, skip the next paragraph.

For the Solid Edge customer, they can buy a single copy of Solid Edge and it is happy to work as a history based modeler. Or, with the same UI, they can use it as a “Direct” modeler – only our direct modeler support parametrics and features ( oh, and it’s all free – no new app to buy. No new downloading and installing.)  Don’t like history based modeling?  You can turn it off and hide it all away. Want to mix techniques in the same part? Why not? This is hugely powerful.  Plus, there is no sending of data to another application or change in the UI.Need customer references to be sure the technology is being used in the real world or a user community that can help you? Yes, we have that too.

OK, I’ll stop marketing now.  The point is, dig deeper.  Do your homework. One debate may be dead but many other debates live on.

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This article first appeared on the Siemens Digital Industries Software blog at