What for edition of WED do you have? Go under in WED,Help,About WED;
In my version there isn't also something like Hi Prec or that. Before months I haven't the A6.3. The older has this functions. But in the newer versions you have more control about building a level and not just LOW or HIGH. To change such properties go under: File,Build WMB, Press the arrow; But the most important settings are these: Visibility calculationa and Light calculations. When you click on one you will see a short help.

Regards,
beegee

--------------------------
GenuineMotors.de