Multiple times I've used the grid fill to fill in circles or edge loops. Whenever I use grid fill with the Shade Smooth option, the corners of the quad fill always poke up a little. Using the Weighted Normals modifier makes this less so, but doesn't actually make it go away.
How can I make it so that Grid Fill doesn't have any weird little pokes and harsh corners when I shade smooth?
Can you post a screenshot? Usually when the shape is too complex to get a good grid fill result, I just go in manually. So if it pokes up a little, you manually scale it all to Z and flatten it or just select the vertex that is doing that and snap it to the level the others are. I don't think I have ever gotten such an issue with grid fill, so perhaps you changed a setting on the last operation panel and Blender remembers it and is doing that.
It depends, but a common trick is to make it an n-gon first. do an inset or bevel which ever is more appropriate. Then delete the n-gon's face(x->face). reselect the edge loop and grid fill. Then reset the normal's vector(alt+n->reset vectors). Depending on the topology you may need to check simple blending in the last operator panel(F9 moves it to the cursor) after creating the grid fill. In some cases, you will need to recalculate the normals afterwards. Depending on the use of the mesh this may be outside(Most common Shift+N or thru alt+n menu) or inside(Shift+ctrl+n or thru alt+n menu)
