From: Vermont, USA
I just went from understanding back to somewhat confused. So according to this chart If I am in heavy woods with 2 trees blocking me from my enemy, his total sighting modifier would be (15+15=-30). The chart starts at 40 so the sighting distance would drop to 10 which equals 70meters. He would have to move within 70 meters to spot me. In the same situation if I was sitting in a Light Woods area with 15 trees blocking me from my enemy the total modifier applied would only be (2x15=-30). This would also drop me to 10 and he would have to move within the same distance to spot me.
The goal was that designers would use fewer trees in Light Woods areas and use the tree models that were smaller and less dense, whereas on Heavy Woods, the more dense and larger tree models would be used and their density would be higher. It's possible that some map designers have moved away from these guidelines, which may be causing the confusion. The intention is absolutely that Heavy Woods should visually look more dense than Light Woods. The additional sighting penalty is intended to reflect more dense types of trees and other vegetation and cover. It's up to the map designer to determine which kind of woods he wants to use and then make the visual look match the game effect.
Also why is the paved road, dirt road, clear, and plowed field not the same as far as sighting modifiers. Imagining someone standing on all four of these terrain types I dont really see how CLEAR can give a zero modifier and PLOWED FIELD can give a -5 modifier. Does clear represent knee high grass or small plants? If so, what does plowed field represent seeing it is the same as MARSH and BRUSH?
Clear terrain is assumed to have more dips and bumps where part of a unit could be obscured, whereas a road is assumed to be flat and without cover. Plowed fields are assumed to have deep furrows that create mini-trenches of a sort.