Hi memo333,
As to closing the gap, have you drawn a line from one corner to another? If that does not work, you probably have a gap somewhere, that needs to be closed. These gaps can be tiny, so what I do to find them is to draw many lines, creating parts of the face I originally wanted to create. That encloses the area of the gap so that you can find it. Close it and delete the lines, your done. Here some screenshots to explain:
So I have the shape and want to create a face.
![Sketchhelp1.PNG](/uploads/imported_attachments/Cg32_Sketchhelp1.PNG)
I want to close it up, but only half of it does.
![Sketchhelp2.PNG](/uploads/imported_attachments/wuVW_Sketchhelp2.PNG)
I draw more lines, creating more faces, enclosing the gap causing the problem.
![Sketchhelp3.PNG](/uploads/imported_attachments/ncyy_Sketchhelp3.PNG)
There it is. Close it and you're good to go.
![Sketchhelp4.PNG](/uploads/imported_attachments/S7SL_Sketchhelp4.PNG)
What exact transparency do you mean?
And try just googling Vray tutorials, there are many good ones out there. I believe Vray actually has a handbook in .pdf, which explains how to use it pretty well.