I have this problem that happens a lot to me when modelling. I like to use the knife projection tool, it makes easier to make some things on a 3D model, however when I apply it, the face gets a strange lightning effect when it has smothness applied, see the image to understang better what I’m saying:
Just so you know, I’ve watched a few Youtube videos to get used to the interface and basic stuff and the rest I’ve learned was on my own using Blender so it might be a really dumb thing.
I already made sure the vertices of a face are on the same plane. The only way I find to fix this is by making that part with a lot more faces and leave flat shading, but I believe it will make render times a lot longer.
Sorry for my english and thank you for your time.