Problems with shading (Normals?)

I am trying to model the negative of a logo (so later on I can pour paint in using the fluid simulator) but I keep getting problems with my shading of certain parts, if it was a problem with normals I was wondering if that will affect the simulation.
I have done the ctrl+n, ctrl+shift+n and flipped normals manually. The problem only seems to occur once I start extruding downwards to create the inside walls of the negative. I am very confused because I didn’t have that problem in another chunk of the same model.
If anyone had a fix it would be much appreciated, otherwise an alternate way to model a negative might work. Picture attached…


make certain you don’t have extra verticies hidden or overlapping faces
the try to do a Ctrl-a to put the normal at 90 degrees
and try again to reccalculate the normal and check all of the, si they are outward not inward
on inside faces
you cn use alss the Shift g then select normal to select the bad normals
this should work most of the time

hope it help

In Object mode, press Ctrl-A to apply scale and rotation. This can sometimes affect the normals in your mesh. Also, I would go ahead and extrude all the faces you need to, and then use Ctrl-N once you are done with the mesh.