What's going on here?

I’m trying to make boolean cuts into the viewing port of this tank, but when I do, it causes massive distortions and graphical artifacts.

What’s causing this and how do I fix it?

did you calculate normal’s outside?looks like flipped normal’s but i could be wrong,also check your mesh in wire frame,and vertices mode.

I’ll bet the faces you are cutting into are too big. See what happens with a few subdivisions on the faces you are cutting into.

hard to understand what you’re trying to do, maybe share your file: https://pasteall.org/blend/

Have you got a subsurface modifier on the mesh?

My file was too big to upload to that site.

Here it is from onedrive.


Your mesh is smooth, but the boolean modifier is creating hard edges and triangles, which cause smoothing artifacts. Turning on Auto Smooth in the mesh properties will keep those hard edges hard.

Your topology is not very good, a lot of ngons, you need to improve, quick example:


also it looks like there’s a problem of normals, go in the Properties panel > Object Data > Geometry Data > Clear Custom Split Normals Data

Have you tried projecting the cutter (metal sheets) on the tank surface?