Hi Matadem, the corner areas of your objects have little sharp "hook" like turns in them at the very ends:







How were these surfaces created, can you post the curves that were used?

My guess is something like a network surface was generated from curves that are not actually touching each other at their ends.

For the 2 surfaces that are planar it would be better to build them using Construct > Planar instead of Network. But before doing that the curves probably need to be tuned up to make them all meet up nicely instead of having space between their ends.

- Michael