Meant to be Seen

I want to buy an Optoma HD66 3d projector, can I get the 3D effect without using active glasses in any way ? or do I need to get 2 projector?

DepthQ makes projectors which in combination with their polarization modulator offers stereoviewing using passive eyewears. However the dual projector route is a lot cheaper than this....
The only way to use passive stereo on the Optoma HD66 is anaglyph and crosseyed viewing i think...
If it's 3d-vision compatible it would work best with 3d-vision active shuttergoggles though. This would also yield the best result with this pj (unless using two and passive....).

I'm not even sure you can get 3D with that even with active glasses, at least not with Nvidia 3D Vision. Please check the official listing of supported displays before you make a decision. And, no, it won't work with passive polarized glasses unless you have two of them and all the accessories that go along with that.