Group Mate vs. Fastened

ethan_1

Does anyone notice any difference  between using a group or mate, such as performance. I personally when mating, especially repetitive things like fasteners, mate one fastener with a fastened mate, replicate it to all holes, group all together, delete the fastened maters. I find this keep things a bit cleaner.

Anyone have thoughts on this? 

Jason_S

Groups are not mates. Groups are just a way to move a bunch of entities relative to each other without having to carefully select all of the entities every time. If your entities were never moving and your design was never changing then it doesn't really matter.

That being said, if you were to change the spacing of holes on a plate, the Fasten mates would respect these changes since each entity has a Mate connector associated with it.



If you were to delete all but one of the mates and just use a Group, the entities would not properly handle this change.



Hope this helps!

Jason

Jason_S

Groups are not mates. Groups are just a way to move a bunch of entities relative to each other without having to carefully select all of the entities every time. If your entities were never moving and your design was never changing then it doesn't really matter.

That being said, if you were to change the spacing of holes on a plate, the Fasten mates would respect these changes since each entity has a Mate connector associated with it.



If you were to delete all but one of the mates and just use a Group, the entities would not properly handle this change.



Hope this helps!

Jason

elaine_parshall594

It doesn't seem like you can achieve the kind of accuracy for center of mass calculations for an assembly by using grouping rather than mates for parts.  

tony_459

@elaine_parshall594, Can you expand on your comment? This would be an issue---if the mass calculations were less precise just because you grouped instead of fasten parts, despite their arrangement being exactly the same. Is this just a suspicion, or did you experiment and compare results between grouped and fastened assemblies? How much error are we talking about? Thanks!

tony_459

@ethan, I do the same. I'd have tens or hundreds of fastened mates in my assemblies otherwise. Plus, it's been suggested to me that groups are better for performance in very large assemblies... Not sure how true this is, but I've stuck with groups nevertheless and use them almost exclusively---unless I have a compelling reason to use a fastened mate. 

MBartlett21

One bad thing about group mates is that, if you are grouping a subassembly in a top-level assembly, it stops the mates resolving in that assembly if you change them, without showing errors either.