CAD Forum

Is there a reason to prefer concentric mate over coincident axes? It seems as if they both make the intention clear. Is one faster to resolve in an assembly? One issue is that lock rotation is only available in a concentric mate.

I see nothing at . . .

http://help.solidworks.com/2018/english ... a53b3b#Pg0

. . . about the efficiency of coincident vs concentric. Doesn't mean there isn't, so it is a good question.

I would say that the concentric mates do show your intent more clearly. Also, I run with temporary axes hidden, so it is quicker for me to do a concentric mate to cylindrical face, rather than showing the axes, setting the mate, then hiding them again.

Dwight

mitchb wrote: ↑Fri Jan 28, 2022 5:36 pm Is there a reason to prefer concentric mate over coincident axes? It seems as if they both make the intention clear. Is one faster to resolve in an assembly? One issue is that lock rotation is only available in a concentric mate.

That's a big one.

Glenn Schroeder wrote: ↑Mon Jan 31, 2022 8:17 am That's a big one.

It's too big to ignore actually.
Reference geometry is imho better to mate to - but WHY is there no lock rotation for an axis/axis coincident mate???

berg_lauritz wrote: ↑Mon Jan 31, 2022 2:34 pm It's too big to ignore actually.
Reference geometry is imho better to mate to - but WHY is there no lock rotation for an axis/axis coincident mate???

Maybe because the people making decisions about implementing enhancements aren't SW users? Or they just rush to get them out the door instead of taking time to properly evaluate them?

I don't have any information to support either cause, but I've seen too many issues with poorly thought-out implementation of enhancements. If someone else has an alternate theory or has information I'm not privy to I'm all ears.

berg_lauritz wrote: ↑Mon Jan 31, 2022 2:34 pm It's too big to ignore actually.
Reference geometry is imho better to mate to - but WHY is there no lock rotation for an axis/axis coincident mate???

I always assumed the answer would be something along the lines of "an axis is a 1 dimensional object, so there is no other vector to use as a reference when locking rotation." But that is a complete guess. It just sounds like the answer that would come out of DSS.,

I have a very firm answer on this. I am unperturbed if this does not meet others' design criteria. I wrote something very long and whatever. I would un-redact if anyone wants it.

* Replace Component with mates, effortlessly without ever picking a replacement face.
* All reference entities are present in lightweight state used in large assembly mode.
* All reference entities are the most stable features, reducing time used in assemblies and drawings.

I do not argue. I openly disagree. You do different, so think different. Great.

Tom G wrote: ↑Mon Jan 31, 2022 4:21 pm * All reference entities are the most stable features, reducing time used in assemblies and drawings.

I can't attest to "all", but I will agree with you for tangent planes (then coincident to this plane).
Never the flip-flop you see when mating directly with the regular tangent mate.

mitchb wrote: ↑Fri Jan 28, 2022 5:36 pm Is there a reason to prefer concentric mate over coincident axes? It seems as if they both make the intention clear. Is one faster to resolve in an assembly? One issue is that lock rotation is only available in a concentric mate.

Don't need to turn on temp axes (and be awash in blue) for a concentric mate.
Plus, I think for most people, concentric comes to mind first for fasteners and such (but I could be wrong on this, often am), as you're looking at holes and shafts and usually not axes.

But there have been times when a coincident "saved the moment" over a concentric, plus for slots (cut or HW), you get 3 free axes.
So, if you don't need the benefits of a slot mate, then coincident can be used (centered at either end or at mid-slot).
Performance-wise, I'm sure a coincident mate is better than a slot mate. And you can't do a Copy with Mates on slot mates.

This is a little off subject, but not much. The Profile Center mate can take the place of a concentric and coincident mate, . . .


. . . and you can usually lock rotation on them by right-clicking on the Mates folder in the tree (sometimes the option is there and sometimes it isn't).

Glenn Schroeder wrote: ↑Tue Feb 01, 2022 9:37 am This is a little off subject, but not much. The Profile Center mate can take the place of a concentric and coincident mate, . . .


image.png


. . . and you can usually lock rotation on them by right-clicking on the Mates folder in the tree (sometimes the option is there and sometimes it isn't).

I love that one - especially because reference axis mates can not be locked I use this all the time. I always have a sketch ready for this purpose - although again - I wish reference geometry for this would be possible.