if you're referring to cs6 extended, it's not an app. You must ask for extended when you purchase CS6. It's included in CC.
3D feature is available with PS CS6 Extended not the Standard one. You could either get the Extended version of PS CS6 or i would suggest to switch to Creative Cloud that not only includes 3D but other great features as well.
For you to look, Adobe Photoshop CC new features | Buy Photoshop CC