It forces you to model it as it is. When going from ACAD to SW this is the number one thing that one is hit with. Modeling as is allows the engineer to see what is really happening regarding fit and function. A 3D model contains much more information than most people realize and SW makes this aspect tolerably easy most of the time.
It allows communication through drawings of this same information by allowing sections and other types of detail that a 2D draughtsman simply wouldn't tackle unless it was extremely important. Back in the days when I used Pro/E we designed a simple stamping (flange and cylindrical chamber). The ACAD drawings would simply show a cylinder intersecting a flat plane. Pro/E showed the fillet in all it's complexity. The vendor was ready to charge more for this detail on the drawing thinking it was something special when in reality that was how they would make it in a stamping die. They were not used to seeing that information on a drawing.
I am always enlightened when other people give their reasons and opinions which always have surprises for me, and I definately learn something on this board.
My two reasons to use SolidWorks are indeed
modeling of solids with hinges which I can set up with a formula to "bend" the hinge so I can stage an Assy file with the hinge part in various positions to mock up hinged parts together with appropriate mates (which works with limitations), and then
eDrawings as a communications tool.
I noted Pete saying with tongue in cheek "Gives us lots of coffee and cigarette breaks, whilst someone tries to fix Solidworks once again!"
Once I gave up on letting my SolidWorks machine on the Internet or a local network, my problems with crashes are very close to zero. There are things in Swks 2006 that I do which cause it to quit but it is only once every month or two.
Some parts are ones I just guess might have problems, so I do "Save As" and it sure makes life easier when something goes wrong, or even right. Then I have both copies of the file and can toss out the lesser design.
Actually, on rethought, I think the ability to think better in 3D and then verify those thoughts with parts and all their interferences and clearances in the initial design is what allows me the ability to expand my design capabilities.
I totally agree - this is the one area that 3d is invaluable in the design creation process.
I am constantly sketch stupid ideas on a bit of paper in the pub - then getting into the office, and as I model them up, I see ways of really improving on them - sparking new ideas that actually fit together.
The down side is that when faced with a deadline or budget constraints , there is a danger of going with ideas that are easy to model, rather than correct for the job - hence the need for easy modelling techniques to allow the momentum of the thoughts and ideas to be maintained even for complex shapes.