Changing the WWR changes the construction makeup of different parts of the geometry, so it isn't really the same. It also affects solar gain entering the building through translucent fenestration.

The values of WWR is different when calculated manually by taking the ratio of surface area of window and walls as compared to the WWR values of the building envelope calculated by the open studio simulation results. I dont know why? Kindly help

Glazing or glass have a SHGC factor, which merely describes about the solar gain by the window. The more the Glazing area and the more the radiation upon it, the more is the solar infiltration. If the window have a very high SHGC then it will have very high incoming solar radiation. The more the higher the Solar heat gain coefficient (SHGC), the more solar radiation is able to pass through the glass. If the window area is high then there is direct formula Q= SHGC X Area, where Q is the heat infiltration. So whether the are or SHGC is high depending upon the climate the heat gains are different.

Thanks, Sharad.