Answer:
3d is 3d. its just 2 images one for left and one for right. RealD is one system for taking the 2 images and polarising them to block the opposite eye. Most home theatre systems have been using XpandD aka flicker or shutter, which uses a synchronised LCD shutter in the glasses to block opposite eye. JVC developed a polarising system for the home that uses alternating rows of polarising filters in the TV screen itself. this system allows you to use RealD glasses at home. however it also reduces the image quality in half, making your 1080 into 540 or standard def.