Idea on Large SW Assemblies

[Jboggs]

I would like to run something by the gurus on here. We have some very large assemblies of our internal equipment that we have to deal with on a regular basis. After suffering through a few years of slow opening, slow saving, crashing, slow re-building, and unexpected sudden errors of almost all the mates, we have developed a few "best practice" habits that I have discussed in other posts. I have an idea now that I think might resolve much of the problem on some of our assemblies.

My understanding is that when SW opens or rebuilds an assembly file it has to individually calculate every single mate in order to position each component. That means each bolt, each washer, everything. And since most mates have more than one possible "correct" answer to those positioning calculations that explains how a file that saved correctly can be a mess when it re-opens. If you think about it, once an assembly is built the great majority of those mates aren't really needed because they don't change. That would mean that most of the parts that don't need to move can then be declared as fixed, or all their mates could be replaced with a single "locked" mate. If a part's position is fixed and it has no defining mates, then SW has nothing to calculate. Well, less to calculate. Right?

Does that mean that once a huge assembly is fully defined that I could go back in there, declare all my non-moving parts as fixed, and simply delete all un-needed mates? If I did that would that make SW manipulation of that file quicker and more reliable? What say you, oh wise ones?

 

[apickard]

If I were going to take that route, I would Suppress the mates as opposed to Deleting them.

 

[ctopher]

I make all hardware lightweight or virtual.

Chris, CSWA
SolidWorks '15
SolidWorks Legion

 

[JMirisola]

Here's my $.02, though a guru I'm not.
I've built and worked with large assemblies in the past and, more often than not, mates that blew up upon reopening had more to do with the type of mate, and how it was used, versus the mate itself. While I do believe you're correct about SWx solving each mate when it opens, the software is much more adept at it than it used to be, so your wait times shouldn't be overly affected by the solving of mates. I'm sure you're well acquainted with sub-assemblies.
Everyone's situation is different. Hardware, software, SOPs, idiot co-workers, etc. can all play into how SolidWorks performs. While I think that going through and suppressing/deleting mates in order to fix the components is a huge waste of time, perhaps that will work best for you. However, if you're still having issues with mates blowing up, I'd spend some time investigating the why versus putting a bandaid on the issue.

Jeff Mirisola, CSWE
My Blog

 

[EEnd]

What I did that made a huge difference in the usability of one of our product assemblies was I restructured it and the subassemblies to minimize the number of mates that were in assemblies marked as flexible. For instance, we use linear slides. Rather than having them as a flexible assembly inserted into the assembly the rail was attached to, I placed the rails in the assembly they were attached to and the carriage into the assembly it was attached to. This created an assembly structure that was different than desired for the BoM’s, so I set it up as a separate configuration.

While a bit of a pain to set up and maintain, the difference in performance while dragging it through its range of motion was significant. It went from 1 to 2 updates per second to dragging smoothly.

Eric

 

[PatCouture]

Has Jeff said, I would think it really depends on your situation and the functionnality that you need. I don't have much experience with large assemblies usually I can get by below maybe 3000 parts with my machine without much issues. Higher than that it becomes a pain.

I guess that if you sort specific mates into folders it can be easy to select and suppress them but other than suppressing every mates and fixing every part I'm afraid it can get cumbersome to use effectively without opening yourself to more troubles than anything. I could see a benefit for when a project is closed and you keep the assemblies as a reference.

Patrick

 

[drawoh]

Jboggs,

I work a lot with large assemblies, and usually, they open okay. I hate using lightweight parts. A significant cause of errors and instability is semi-qualified CAD operators updating the model.

I try very hard to keep my catalogue parts simple. I avoid redundant mates. I minimize the number of top level configurations. When I am done designing, I eliminate the in-context modelling from my fabricated parts.

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JHG