vray for rhino rendered glass white instead of clear

[Guest maymei]

Hi Everyone,

 

I am currently rendering for my project and the glass in my building would not render clear. They have only been rendering white. I tried adding reflection and refraction layer, tried adding an emissive layer, lower the fog multiplier, brighten its color, changed the sun angle. Nothing worked. Any suggestions? I would love to have clear glass so the structural columns would show up. Also I applied black generic material to the railings but they also rendered black. Are they related to the same problem?