REVIT RENDERING TURNS OUT BLACK/WINDOWS MISSING

[s3455556]

I have followed  step by step guide on youtube on how to apply sun light to my revit once rendered. Only thing is, it turns up black. ITs very fustrating as I have tried everything and nothing is changing. I take a 3d> go to view> go to render> settings are DRAFT, RESOLOUTION=SCREEN, EXTERIOR=SUN LIGHT ONLY, STYLE=IMAGE (INSERT IMAGE OF LANSCAPE THEN RENDERand it turns out like this!??

Though the image renders dark,when i play with the exposure the windows have actully been deleted from render all togeather.

Before render image of room 

[L.Maas]

First of all, your windows must have a material which is (partial) transparent like glass.

Second you have to look at your render settings

There maybe other causes, but these seem to be the most obvious

[s3455556]

Nope, i have chnaged the glass transparency about 10 times, from 75% to 100% )just to see if it would work, but, no. As you can see from my screen shot the settings are all to order as they should. 

[L.Maas]

Did you also set the daylight portal options as in my screenshot? (not part of your screenshots)

Otherwise can you post (part of) your project so that we can have a look at it.

[s3455556]

What window material would you recommend? I've changed it about 10 times
and had no luck.

[L.Maas]

One of the glas (clear) form the autodesk library should be working Ok.