well -<{ JB }>-, that method (the heavy glasses) is used when u have a bigger budget......because what is heavy is expensive but the main reason is that those glasses are controled electronically by an emitter (that controles the range of the signal and enables the viewers to experience the effect from anywhere in the room) that gives glasses info on wich of the projected images goes to each eye respectively....that is called shutter glasses. u have this kind of systems available for your PC at www.stereographics.com (no i am not making pub...) they aren't very expensive and u can really se your 3D stuff come to live, i think it is awesome the polarized scheme is for lower budgets, u can even use those paper glasses that have polarized lenses that the effect is good but not as good as the shutter glasses cheers!!