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The T-buffer's primary task is to solve the aliasing problem in 3d graphics. Aliasing is under-sampling of an image, which causes graphical artifacts on screen. The T-buffer will allow for full screen antialiasing in real time.
In simple words, the T-buffer works by storing and combining multiple renders before a scene is displayed. If you want a certain effect, you run it several-times and the T-buffer will perform additive writes into the back buffer for each successive pass. When complete, flip the back and front buffers to display the final image, and repeat for the next frame. For effects such as motion blur, soft shadows/reflections, and field of view, the T-Buffer will draw between 4 and 8 renderings from different perspectives (remember it's not just positional perspectives) to create the appropriate effect. For motion blur, the T-Buffer will store images of the object's motion through time to create a "multiple exposure" effect, which at high speeds can effectively simulate motion blur.
The same general principal is used for depth of field effects. By storing multiple renders of a scene through different focal settings, the T-Buffer creates an effect where out-of-focus areas appear to be blurred with misaligned additive layers, while the in-focus distance remains sharp.
Now that we have a basic knowledge for the kind of effects the T-Buffer can create, it's easy to see how it can implement effects such as realistic shadows and reflections. Touted as "soft shadows and reflections," the effect is prevalent on smooth or semiglossed surfaces. Reflections and shadows close to the surface are sharp in crisp, and they become increasingly feathered and blurred as the distance to the surface increases.
Using the T-Buffer, we can assume that a similar multiple-render technique is used for both reflections and shadows - by adjusting the transparency and angle for each reflection/shadow pass, the additive effect near the surface will be sharper and clearer, and the effect will taper off as the additive translucent layers separate by angle.
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