A simple, but excelent, FAQ that helped me understand how to construct good looking V-shaped roofs.
http://www.ryandor.com/forum/viewtopic.php?t=128&highlight=roof
Another pointer: Try experimenting with the lowest altitude (i.e. z=20 according to the guide) a little. I tend to increase it to say 21-25 in order to get the best result. The OSI roofing tiles do not follow an
exact pattern when it comes to within/base height. You will notice this if you fiddle around with them a bit.
Also,
"allways" make sure you have the sloping (decending?) part of the roof towards the longest of your structure's walls. This will ensure you do not end up with an unproportional looking roof. Since the increase for each row of roof-tiles is z=+3, if you have a roof that covers more than say 20+ tiles it will look rather odd. Experiment with it
Creating L-shaped roofs is a bit more tricky. Make sure you select the correct roof-type, one that supports turn-tiles. Or, if you are dead set on one particular roof-type, do the roofing in two levels.
For example:
XXXXX
XXXXX
XXXXXVVVVV
XXXXXVVVVV
XXXXXVVVVV
XXXXX
XXXXX
Where:
X= goes from north to south
V= goes from north to south
Sorry for the bad example.. Its kinda hard to illustrate without a screenshot. Hope it helps.
And best of luck!