Solid geometry is huge for me. Modeling with surfaces is a pain in the ass. The difference is like making something out of clay vs cardboard box. Sketchup is a surface modeler. While I generally like the ui of Sketchup, all those surfaces and edges can get messy and you can't do binary transforms on them.
For example, to make a hollow box in Sketchup you create a rectangle and extrude it. That gives you a hollow six sided cube. In viacad you make two cubes, one smaller than the other and subtract the smaller from the larger, the smaller being the size of the void. In openscad you do difference() {cube([ox,oy,oz]); cube([ix,iy,iz]);}
What openscad let's you then do is this:
module hollowbox(width,height,length,thickness) {
difference() {cube([width,length,height]); cube([width-thickness*2,length-thickness*2,height-thickness*2]);}
}
Then to make a hollow box I can do:
hollowbox(10,20,30,1);
Forevermore. Brilliant!
I encourage anyone to try it out if they haven't done so yet.