pattern vs instance 1

[skanskan]

Hello

Could you explain the difference between "pattern feature" and "instance geometry" in NX8, please?
I know there are several threads about it but it's still not clear for me.


I understand that "create component array" is only for assemblies.

thanks

 

[JohnRBaker]

Well to start with, 'Instance Geometry' is just that, for geometric objects, such as curves, bodies, faces, edges, etc., whereas 'Pattern Feature' is for creating patterns of actual 'features' like holes, pockets, bodies, curve features, etc. And while both functions will work with Bodies (solid or sheet), that's the only real overlap. Now it may look like curves also constitute a common set of supported objects, but that's ONLY if they are 'Curve Features'. If they are simple curves which are not considered 'features' then you cannot use them with Pattern Feature (the same is true to 'Point Features' versus simple point objects). Datums is another item which can be both 'Instanced' and 'Patterned' but there are some restrictions and limitations, so it's still not an exact duplicate.

That being said, the biggest difference is that 'Instance Geometry' creates a single 'feature' which can be edited, but the 'instances' are themselves 'dumb'. Granted, if you created it associatively, editing the master object will cause the copies to update, but the copies are not considered their own features, just part of an 'Instance Feature'. However, with 'Pattern Feature', not only is a 'Pattern' feature created, but each of the 'members' are still features in and of themselves which can be edited individually (based on the parametric extent of the original 'feature').

Also note that 'Pattern Feature' is slightly newer, and is based on a general 'pattern service' toolkit which is also used inside of Sketches (starting with NX 7.5) and will be the basis for the function which eventually replaces Assembly Component Arrays (post NX 8.5).

Anyway, I hope this helps explain what the differences are and how you go about deciding which function to use and where it might work best.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
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