3Ding is a radical form of RC flight.

It involves things like "hovering" the plane. (Considered by most to be the most impressive part of 3Ding.)

Hovering is "simply" hanging the plane by it's prop (while flying of course), and requires that the thrust to weight ration be greater than 1:1. In other words, if the plane weighs 35 pounds (as many true 3D palnes do), then the engine must be capable of producing something like 40 to 50 pounds of thrust. This will also allow the pilot to accelerate vertically (or climb) out of the hover.

Good 3D pilots can touch the rudder to the ground while hovering.

There are usually many more maneuvers performed during a 3D flight. Torque rolls, tail slides, rolling circles.... the list goes on and on.

During 3D competitions, these flights are performed in time to music which can make them truly spectacular.

What I DON'T like about most 3D flying is that it is often not true to scale. If it were possible to perform some of these tricks with a real plane, they would most likely kill the pilot from excessive "G" forces. That being said, full scale aerobatic pilots have been paying close attention to what these 3D pilots are doing, and some have incorporated maneuvers into their routines.
Dennis-