There is no definitive, specific software to 100% replicate glass. Most modern rendering packages like ‘Mental ray’ and ‘Vray’ which I use give you a material shader they class as ‘realistic glass’ and that is a far as it goes. The rest is artistic licence.

1. What  you are reflecting is the biggest consideration. For the majority of Architectural visualisations this is anything  within 10m of your scheme or for that matter anything that adjoins the site at that time. If your visualisation is part of a Masterplan which does not exist yet or a blank site then anything goes HDRI maps are great as you need that ultra high highlight for specular highlights. If the Visualisation is a ‘Concept’ but needs to look ‘real’ then I find highly specular greyscale maps in the reflection slot of your visualisation work a treat. These greyscale images are great for metals also. I usually add some into a scene for interest.

2. Transparency of the glass. This is effected by the angle of viewing and whether there are any lights on inside the building. A simple rule is Less internal lights = More reflection. Therefore at night with all the buildings lights on, reflection is minimal, unless the viewing angle is severe.

Other things I feed in are variations in the glass and the fact that most pieces of glass are installed +/- 3 degrees different to each other even on a flat elevation of glass. This is what gives the look of glass shown on my attachment ‘flat’ glass.

Another thing to bare in mind is that if you are faceting or adding an angle to any reflective,refractive object. For example take a diamond. The beauty of a Diamond as an object, is the fact you never get the same reflection twice due to the highly skilled cutting of each face. In a building of angled glass the reflection will change as you walk around the building. When you are head on to a pane it is transparent, and as the angle increases you get more reflection. Generally with glass there is no, ‘this is the refection’ one liner, for that you are looking more at mirrored glass, but even then its all relative to the angle of the viewer.

Glass in 3d visualisation is a minefield as there are so many possibilities and external factors. Probably the best way to look at this problem with your Client or Architect is to produce an image everybody falls in love with and then go to the glass manufacture and say…. we want this. This has happened to me, so Glass manufacturers and Architects beware.