Hi Bartosh, so as far as the filleting goes, it can be difficult for fillets to be calculated on surfaces that come fairly close to being smooth to each other but actually meet at a shallow angle like the side pieces you have here. Fillets in such cases will tend to be very very small, fillets shrink down to 0 size at places where things are actually smooth to each other.

So for something like this with a patchwork of "almost smooth but not quite" surfaces meeting each other will not be likely to be filleted and you would need to use an alternate technique like you did.

- Michael