Frosted glass effect

Depending on the look of "frosted" - you can probably do a faceted design via a normal map and a refraction distortion scale property, for something like TS3's shower glass.

http://i.imgur.com/bjfpbTY.png

Otherwise, if you want to do frosted in that the glass isn't clearly see-through, but still lets light through, like this:

http://i.imgur.com/nILuqX6.png

I don't think that is quite possible, at least not directly. You may be able to shrink the facets of a normal map to be so small they can't be individually seen, but also, that may just end up looking like a sheet of glass covered in noise. :/ That type of effect seems a bit out of reach for TS4, seeing as it can barely handle regular transparency :)

The second effect can be achieved by recoloring the diffuse image for the window's glass. The three windows below show the same window. The left is the original glass, the middle is using EA's frosted glass diffuse texture, and the third is the original layered on top of itself 3 times to increase the opacity of the alpha image:

http://i.imgur.com/BFufMkD.png

If you also wanted to reduce the amount of light coming through the frosted glass window you could edit the Light resource in Studio's Warehouse. It seems that lowering the number in the Intensity field causes less of a light effect from the window:

http://i.imgur.com/J1RmXIy.png

For that textured effect, then, you'd use a normal map. You'll want the glass to be using the "GlassForObjectsTranslucent" material (In my experience, it's the only one that supports the material entry you need), and for it to actually get the glass to blur what is behind it, you'll want that material to have the "RefractionDistortionScale" property, and a value of somewhere in the 0.15 to 0.20 range should work, depending on how drastic you want it. :)

Keep in mind, that you'll have to have some kind of texture (like that nubby-rough texture your example has) for the normal map to work, as it needs to catch the background in order to scatter it. A smooth blur, as in my second example, would be very difficult to achieve, if even possible - OrangeMitten's method would probably be the closest possible to that particular effect.

Interesting, thank you.

Ah, yes, I suppose that method does work. I was thinking of glass that actually blurs what is behind it, rather than regular glass that is just less transparent. :)

Actually i meant the glass that blurs what is behind it, like this http://pre10.deviantart.net/adcd/th/pre/i/2011/037/9/1/frosted_glass_by_janhatesmarcia-d38xvru.jpg