vraysun reflaction on curtain wall

[roysgi]

How do we create an effect of the sun reflection on the curtain wall ? (Like the picture attached)
I want to use only vraysun and sky without using HDRI

Using glass ball is fine, but on a flat glass surface this does not happen
Thank you
Roy

[tashko.zashev]

You need to adjust the sun position according your point of you and you will see the reflection of the sun over the glass.

Here is one simple scene setup (Max 2013):
Sun_Shine.zip