You mentioned the learning curve with DesignSpark. When I first started doing FPGAs I thought "I don't need these silly HDLs, I'll just draw schematics!" Then I realized that 30 minutes drawing a 7 segment decoder in gates reduced to 2 minutes of writing Verilog and I switched.
I've gone the same way with 3D CAD. It is seductive to drag and drop graphically, but for things like I do (front panel layouts, etc.) describing it programatically is the way to go. OpenSCAD does a credible job. If you look at Thingiverse's customizer, for example, you can find designs that let you tweak key parameters and get a custom object out which is a great example of what I'm talking about.
@Etmax: Now spare a thought for the amazing people that did all of this with a slide rule and some graph paper :-)
I agree. One thing that this projec has made me very aware of is just how difficult it is to pull an entire system together including the enclosure and HMI (in the form of switches and meters in my case :-)