OK, I wanted to make a head for my character. So, in MED I thought I would take a sphere and then turn on vertex mode and move vertices around until my sphere looked more like a head. Then I realized it was really hard to be perfectly symmetrical with this so I decided to select all the vertices on the right half of the sphere and press delete. I clicked OK, OK to the prompts and then proceeded to try and model the left side. When I got it to a good shape I clicked the mirror button to create a mirror image of it. Then I rotated that and tried to place it perfectly on the other side. When I took a look at my work in the 3D preview window and in the engine preview I saw big gaping holes in my head! I'm not sure what I did wrong. Is this not a good approach to modeling a head for a character?