I know this has been asked many times before, but I can't actually get a simple answer that works for me.
How do I create glass for windows. I've had a go at cube maps which don't really produce good enough results, so I'd like real reflections if possible.
I'm also having trouble controlling transpareny of the reflective material.
I don't understand why there is such a reluctance to writing such a shader that handles real-time reflections and transparency. What's the big deal?
Looks like many users here are asking for such a shader.
What does it take? Days, weeks of work?
Looks like I'm going to pay someone to write this shader and then I'm going to share it for free.
"True" reflections are possible - at least for planar objects like windows and water - but not easy, thus you can't get a "simple answer". You should prepare to learn how the rendering pipeline works, how render textures work (Unity Pro only)...
You could also take a look at http://www.unifycommunity.com/wiki/index.php?title=MirrorReflection2, there is a mirror shader which can quite sure be adapted for a "true reflection and transparency window shader". I do not know whether this shader works for Unity 3 (seems some have to be ported first). Another shader to look at is the water shader which ships with Unity Pro (especially for the setup script and stuff).
You see - another not-so-simple answer, because true reflections are quite a complex topic in real-time computer graphics (because real-time raytracing isn't possible - right now).
You didnt state if you are using the free or pro version of Unity. But as I've been told (currently using the free version only), certain features with shader and shadows has been removed from the free version - so you might have to "fake" some features.
One of the important features regarding your problem might be "real reflections" as thats something "raytracing" programs does, eg. real 3D rendering programs. Unity3D is a GAME-ENGINE, not a RAYTRACER.
You can get realtime shadows, because these can be calculated from vector-coords. If I was to produce eg. a mirror, I would use the PRO version, then map a "rendered texture" where the texture is comming from a secondary camera facing in the direction of the mirror. This is the closest possible way I think so far, unless I've misunderstod Unity3D engine.
With transparency, its a matter of "alpha transparency", but alpha does not "index" your view-rays, for this you also need the shaders to do the trick. So look at the water-materials and see if any of these does the trick. Again, I think you will need PRO license to use the shaders for something "really beautiful" but I might be wrong.
Hope you can use these advices.
I’ve also been searching for a glass shader with dynamic reflections. I eventually managed to make one, by modifying the MirrorReflective shader/script to include transparency, a base texture, and tinting.
I made a page for it on the Wiki: http://wiki.unity3d.com/index.php/SurfaceReflection
It requires Unity Pro, though.