I'm a blender newbie. I'm trying to build an helmet, and I've got to the point where I have to cut the global object I've built so far to get the visor.
Here, the shading is weird:
I thought maybe was just something with the calculation of the new normals so I used Tools > Shading: Smooth and now the weird "box", the most visible problem, is gone. That line on the upper side, however, remains.
How can I fix this? Is there something I can do or is related to something I did/didn't do when I cut the faces to get the visor shape?