A CAD smackdown – direct vs. parametric modeling
Yesterday’s CADalyst CAD magazine, host a webcast about “Direct vs. Parametric”.
Topic: When, why and how to use direct and/or parametric modeling in your business.include
I agree somewhat with Matt Lombard, I find the title of the debate inadequate. Let’s not forget that I have Solid Edge vision on the topic…
« .. First. The title. Direct v Parametric. Some of the panelists weighed in on this too. I think it would be better called Direct v History. Almost any name you could come up with has some flaw, but to me, the two competing interests here are Direct editing and History modeling… »
It is possible to have a design that combines direct editing and parametric.
Example if I take a direct editing function
I can push on one a face,
and a feature will be add to the pathfinder along with a parameter in the variable table associate to the direct editing move.
Now if we look from another angle, history vs. non-history.
Again, it is possible to have a design with both approaches.
It is possible to push on the same surface, without any entry being record in the history of the part.
If we push the comparison a bit further, it is possible to have the parametric without history. Here, no entry is found in the Pathfinder, however we have a parameter that controls the topology of the part.
Now what will be the real debate, related to the introdution of new technologies for modeling and editing?
Ok I am probably the only one to approach the debate with this vision, but I am firmly convinced that it reflects much better the real debate.
It is not whether we have a historic or not, if we have parameters or not, because he can mix all techniques in a single environment.
The question is how can I navigate within my design to create it or modify it?
Can I quickly change the behavior of my design to promote a change that has not been predicted?
Does the position of holes must always be defined in relation to the edge of the part, or the reverse may be possible?
Why I cannot lock a portion of my part, without affecting the rest of my design? *
Perceive the debate with a linear or nonlinear vision better reflects the true nature of the debate and helps better understand the cultural shock and transformation happening in the CAD community.
* For SW users who request the possibility to lock down some of the features, within synchronous you can define a ground relation on a set of faces, locking down their position in space. Non linear modeling supports this as a native behavior.