Building a Helmet - Dynamesh Subtract

1. Creating a sun visor.
2. Subtract a cube from a Flat Sphere using the Dynamesh Subtract method.
3. Make sure Flat Sphere is in Dynamesh active mode.
4. Place cube layer (selected subtract icon) under flat sphere layer (selected union icon). 
5. Merge the Flat Sphere layer down into the cube layer.
6. ReDynamesh layer.