need help with smoothing on a vault

i’m making a safe for a video game, but it has really ugly smoothing and i’m not sure how to fix it.

here are some pics:

you can see on most sides that the smoothing looks really weird. is there any way to fix this without marking edges sharp? i made the safe by spawning a cube, scaling it to the right size and beveling the edges i want as rounded corners.

Have you tried “Auto Smooth?” It’s on the Object Data tab, under “Normals.”

If you don’t want sharp edges, you need to add some “support” edges by making some loop cuts near (but not too close) the beveled edges to make the shading better for the part that is flatter.

Or, you could simply add 1 or 2 segments when beveling (while you are beveling use the mousewheel to add or remove a segment, or press numpad+ or numpad - , or just press F6 after validating the bevel and adjust the amount of segments) , the added segment should provide the same visual shade correction as the manually added loopcuts

Or if you can’t add segments, you could try to select a face and press I to inset it to see if it can provide the edge support those faces need to remove the ugly shading

Try going in to edit mode and selecting all then hit ctrl+n to recalculate the normals (though I don’t think that’s the problem). If that doesn’t work it’s the shading when you click on shade smooth. I get that too on things that I don’t want to put a sub surf on. Course I’m also not sure if it’ll stay like that if you put a different color material on it. Try clicking on shade flat in object mode to see if that’s what caused it in the first place.

Did the mark sharp help with the shading or no?