Realistic 3D Shadows Render in Photoshop

There are many techniques of creating shadows in Photoshop but today I will show you how to create realistic 3D shadows using Photoshop’s 3D features. You will learn how to cast realistic shadows of your models or objects and render the shadows only.
Contrast Masking – Masking/Extracting Shadows

Masking shadows is difficult let’s face it and this is a problem that had no easy solution for me until now.
If you want to replace the background of a model shot for example, how do you keep the original shadows on the new background without having the texture of the original background over them?
In this video I will show you how to incorporate the original shadows of an image on a new composition using blend modes, levels and some masking. Really easy and awesomely useful especially for photographers that need to replace backgrounds.
Original article about contrast masking: http://www.earthboundlight.com/phototips/contrast-masking-photoshop.html
Man stock image: http://mjranum-stock.deviantart.com/art/Fly-1-255405147