>>41769390Subdivision surface, in 3D graphics, is a method of creating new, smooth polygonal data from a simpler mesh by averaging the position of each three connected vertices (something to that effect, I don't care for the math).
It creates smooth and even round surfaces, see pic related. To put it in Pokemon terms, it's the joke behind Porygon2's design.
Subsurf modeling is where you use this modifier to create your final model (as opposed to completely different workflows like sculpting). The basic gist, beyond just box modeling, is that you control the placement of the geometry to manipulate where the average points that are created get put: for example, a cube evenly loses volume and approaches a sphere, but if you have an additional edge loop and move it close to the existing outer edges then you make that outer edge in the final product more square (ie, if every edge had a second edge loop you'd end up with something closer to a rounded cube)
Subsurf modeling, in its most primitive and pure form, looks something like the original Toy Story (the most prevalent algorithm for it, "Catmull-Clark", is named after its creators; one of whom was Edwin Catmull, who was Pixar's first president): very high-poly, very round, but very basic in shape.
That's the benefit of it, in a nut-shell. You can easily create very high-poly models with a fraction of the work and resources. The negative is that it's primitive, and going beyond basic shapes or broad details is outside of its scope and is not remotely feasible compared to simply sculpting instead.
That's probably more detail than you needed. tl;dr, what I originally wrote. The new Pokemon are nearly all- barring specific 'hero' models like Eternatus- broad, mathematically simplistic shapes- and often very spherical ones at that- to make life easier at the model library's pipeline because it's almost certainly subsurf exclusive.
If you followed all that, the other points should be self-evident.
