Reflections in windows
 

can anyone tell me how I can project a sky texture on the windows of the building I'm modeling?

I've heard something about HDRI but I don't konw if it's the proper tecnique for this problem.

thanks in advance

hdri (High Dynamic Range Imaging) is a lighting technique it's not necessarily just for doing reflections (although it is good for that!).

What you need is an image taken at 13 or so different exposure lengths to get you the full range of brightness in the image. This is then used to light a model without the need for lights. It's more complicated than this so it's worth investigating.

But for what you want you may be able to just use a env dome and raytrace the reflections onto the windows from that.

Alan