It seems photographer Pat David found a model patient enough to provide us with unlimited experimentation on Portrait Lighting. Unfortunately, it’s a 3D rendering of a really creepy bald headed dead guy. I think I would have preferred a hotter female, or maybe an Orange..
Just ignore the cadaver, and adjust the lighting until you achieve the desired effect. Much faster than physical manipulation, and you can combine multiple light sources. It should make pretty good prep work for a shoot where you have a specific look in mind.
Here is the link. The software can be downloaded and manipulated to your heart’s content. (Although you will need to download Blender.)
For simpler reference, it may be good to grab a copy of this portrait lighting Cheat Sheet- also listed in the link:
This is the kind of card that would usually ends up taped to my light boxes. It looks dumb and hokey, but you’ll be surprised how often you reference it- every time you adjust your lighting.