I created one half of the head, tried duplicating it, scaling -1 along the x-axis and then merging, but it won't create polygons between the two meshes. I got it to work once, but I haven't since. What am I doing wrong?
When you create a merge you got a tolerance value which define the distance of atraction between the two object....this allow for great real time blending as you move the points.
If your points lay to far from the tolerance value they wont merge together. Also you can enter a greater value than the one allowed by the slider....
If you want more details take a look at the dog tutorial on my site
RCR