External References – Why I hate them.

Posted on March 31st, 2010. Posted In Personal,Rant

I know, this subject has probably been discussed adnaseum but I don’t care. This is my blog and I write what I want. Today I want to write about why I hate external references. Specifically, why I hate it when someone creates an entire assembly that is so intertwined with external references that it’s next to impossible to change anything without blowing up everything else. Hold on, I need to take a deep breath here.

I took on a side job where I’m managing an assembly for a small company. 99.99% of the time this wouldn’t be a big deal, right? This particular assembly has a skeleton sketch, though. Again, not normally a big deal as skeleton sketches often only control the assembly and the placement of parts/sub-assemblies. Uh-uh, not this one. This sketch not only controls part placement but part geometry as well. I can’t even begin to describe how frustrating it is to try to fix a sketch only to see that, while it is fully defined, it doesn’t have a single dimension on it *and* it’s miles away from the origin. Perhaps this wouldn’t really matter in the big scheme of things, but every single external reference is broken. All of them. There’s only 54 unique parts in this assembly, but when every sketch entity is defined by at least one external reference…I’ll let you do the math on it, my head is starting to hurt just thinking about it. Again.

Look, I totally understand the need to occasionally create parts in context. I do, I’ve done it. However, I don’t leave those relationships after the part is created. Sure, it’s nice when hole A drives the size of hole B, but just at what point does enough become enough? Seriously, everything is driven by the assembly sketch. Can you imagine the carnage that would ensue should someone accidentally modify that sketch? The collateral damage (keyboards, mice, monitors) alone would be staggering.

The assembly I’m talking about, in the end, has 666 parts (a bad sign to begin with?) with only two sub-assemblies and it takes forever to open. Aside from the fasteners, and their patterns, almost every part has an “in-place” mate. This I find especially annoying as it goes against how I believe an assembly is created, and you all know that I am always correct. I’ll pause here for laughter. I’m sure that the originator of this assembly had only the best intentions when they created the original file; then again, so did Dr. Frankenstein. However, in creating such a monster, the mad scientist neglected to leave any information regarding the proper care and feeding for said monster. This, my friend, just exacerbates the situation. If you’re going to leave such an abomination for future generations, at least have the common decency to provide some notes regarding your thought process so that we, the unfortunate heirs, can have a chance at understanding what’s going on. It makes me thankful that I don’t drink to drown my sorrow, otherwise I’d probably have drunk myself to death.

I think though, the worst part of it all is that the overall assembly is so incestuous, that I can’t move the part sketches to their corresponding origins without wreaking all sorts of other havoc. I’m hopeful that once I’ve gone through everything and removed all the in-context bs that I’ll be able to have more control over the assembly. I’m not overly optimistic, though. It wouldn’t surprise me if the mad scientist has some other diabolically created mates or relations that will continue to aggravate me.

Thank you, dear reader, for allowing me to rant. I’m not 100% sure how much sense this post will make, but I certainly feel better at this very moment.

By a show of hands, how many of you have tried SimulationXpress, or any of the ‘Xpress’ products available in SolidWorks? Sure, they’re meant to be like gateway drugs, tempting and teasing you into purchasing the full-blown product, but that doesn’t mean that they’re bad for you.

SimulationXpress is a decent, first-pass, analysis tool. It’ll let you know if your part is in the ballpark, though I wouldn’t base my final design off of it. You can find it on the ‘Evaluate’ tab of your Command Manager, or under the ‘Tools’ dropdown. It’s a simple tool to use just by following the prompts. The wizard walks you through the necessary steps to run an analysis of a part so that you can have an idea of how it’s going to react.  It is limited to force/pressure analysis but, again, you’re just going for a ballpark idea here.

Where SimulationXpress, and its fellow Xpress tools, are already in every seat of SolidWorks, don’t you think you owe it to yourself to try them out? As I’m so fond of saying, if I can do it, anyone can do it.

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