First, i dont know a lot about what you are designing but, i would recommand you to do this part as an assembly of SYNCHRONOUS sheet metal parts with weldments. When you'll want to find the internal volume you can do a internal volume part/body by creating a volume by stitching copied surfaces from your model.
Thanks, but no thanks. This model works fine in ordered. Why should I drastically change methodology to workaround the limitations of sync?
I want the volume to be automatically derived as the model changes size due to the user changing the overall dims.
Not sure of your method with stitching copied surfaces: would it be auto-calculated as the model changes and can I assign that volume to a variable.
So I misunderstood your first question -- I was multi-tasking when reading it. What is true is that you can't use a driven variable in an equation involving another dimension in that same sketch. And Synchronous is all solved at once just like 2D sketches are, so same issue.
That said, if you want to do what you are doing in Synchronous, use Measurement Variables instead. When using the Measure command, choose the little variable table like button on the ribbon and it will make a variable in the variable table for this measurement. You should be able to then do it just like you always have.
Well, you cant really blame solidegde if your model doesnt represent reality. This is not a part. It cant be manufactured , it is an sheet metal assembly. If decide to do it as an welded sheet metal parts assembly, you'll have a lot more control on your model, your draft will be easier to do, you'll be able to dimension your weldments,and you'll be able to find the real volume (not approximate) inside your part by creating an ''volume part''. You'll also be able to put the sheet metal gage and bending properties. Youll be able to get the bends table and flat pattern. Thoses seems like a lot of improvements. Maybe you should drastically change methodology to work work with sync.
No, no and again no. This part works for our needs. I understand what you're saying but it's overhead that gets us nothing.
Thanks for your help but I'm going to try the measurement variable thing.
That (measurement variable) works very well. It's new to me - never knew about it. I guess it was hiding in plain sight. Thanks.
Still don't get why there can't be reference only dims but now I can chillax
"Still don't get why there can't be reference only dims"
I believe it's because there's no hierarchy to the features, sketches, etc. in a Synchronous part. So when Synch is computing a change it's not capable of making that decision.
Again Synch does not depend on sketches the way Ordered... and this you'll eventually get to appreciate.
Dan's solution is just as, if not more elegant.... I also didn't know this.
Thanks, Bob. I'm not using (keeping) sketches in sync and I already appreciate the difference. It's just annoying to lose functionality or to have to "fix" parts when moved to sync. I'm just wondering why PMI dimensions couldn't include a reference only type. I'm sure it could be done if there was demand for it. Anyway, the measure variables work as a substitute and it's a nice new trick to have learned.