Hi caldreemn, wow that's a very detailed model!

So for your first question, a sort of scalloped out cut like that can be done by building a cutting surface using things like loft or sweep and doing the boolean with the surface as the cutting object. That's instead of using just a 2D curve as a cutting object since that will be a straight direction type of cut.

So that looks something like this, here using sweep and boolean difference:











You can adjust the shapes of the sweep profile and rail and also the angle and depth of the surface in relation to the main body to get different looking cuts.


For the base geometry, judging from the patch junctures in these areas I'd say it is likely conversion from a sub-d model for the base shape:



- Michael