Intersection Priorities

[Zendrix]

Hi! its me again! 🙂

I have 2 situations:

1. A slab with finish layer of ceramic tiles, which follows through the "niche" of the window at floor level. the ceramic floor is stopping and is being ivaded by the stone material. I understand its a matter of material priorities, but i always had this concern: if i make something work for a specific situation, cant i be messing with the normal intersection settings of the whole project? 

Example: if i set the priority of the ceramic tile higher than the stone structural wall, cant i be opening the gates to many irregular situations regarding intersections of ceramic tile and granite?

2.i have the slab making the "niche" corners cause it seemed more logical, once the stone walls normally go to the ground in this type of construction. But when i place the door, and because the opening is a specific type, it seems the 6cm width that the shape makes on the walls is affecting the ceramic tile on the floor, replacing it by stone.

[Zendrix]

any idea why the reveal of the door "eats" away my slab?