Come on, Chris. You're really gonna tell that instead of engineers getting to grips with basic mathematical principles we're gonna dumb down the software? Sorry, I'm with Lew on this one.
SIGH..................................................................................................................
Nobody wants to dumb down the software.
There is, however, a practical consideration..... You and Lew are basically demanding that everyone should do a complete analysis of every dimension prior to starting up the software. That every part must be fully defined, before one has any right to begin with CAD.
That CAD is basically a DOCUMENTATION TOOL, used only to document in a model what has been fully designed and tolerance checked on paper, and that such is the only "PROPER" use of CAD.
Sorry, boys, but while SOME users need to do that, CAD is a very useful design tool for basic "what if" type "clean sheet" designs. I use Alibre for that.
I also have some clients who give me "engineer's drawings" that simply give some overall dimensions and structural member sizes. What I do is to "detail" those, working out the dimensions required to show a set of parts which will assemble to form the structure wanted. Drawings telling the shop where to put holes, what length to cut, etc, to make the structure as the engineer's drawing shows.
Particularly with use as a design tool, but also with detailing, some dimensions are derived, measured off the model. Yes, in many cases they could be calculated to some number of places accuracy, but that seems remarkably silly when you have the "built" structure right there, waiting to be measured.
Doing an exhaustive evaluation of the tolerances is just never done for these structures. It is not necessary, the basic allowances are KNOWN to exist in the hole oversize standards, and the fact that parts can be "drawn-into" alignment if the shop is off a bit.
What is needed to make this more do-able is the "tolerant fit" constraint that has been described.
That takes care of the dimensions that will NOT be followed to better than 1/32" (steelwork) AND the various oddities that Alibre comes up with from time to time, when it says that 4.000000 does not equal 4.000000.
I will point out that this is not "dumbing down", it actually is allowing actual effective use of the tolerances which the design allows. Enter the tolerance in the "tolerant fit", and you get a check on whether you are in fact hitting the tolerances with the parts you have defined in CAD.