Isometric engines have some advantages such as giving a 3D look without the effort, and I am writing a game using one. But I dislike the way tiles closer to the camera can obscure tiles closer to the player in the game. What do you do if a player walks under a tunnel or into a building? Do you still show what the outside of the wall even if the player cannot see the outside wall? What about a real 3D landscape where line of sight is in 3D? Or a mineshaft that the player has just climbed out of. Answers or workarounds appreciated.

Many iso engines, perform a semi-transparency on tiles that obscure the player character, and the area immediately surrounding the player character. UO, Diablo for example. That way you can always see your self.

Similarly many engines use a depth limited line of site algorithm to display only things the player can see. Again see Diablo for a good working example. One way to accomplish this is just paint a fog of war around the character, so the player can''t see anything that the character can''t.

Hmm yeah any idea where I could get some info on writing a "fog of war" the calculations must be pretty advanced?

I presume you just have to do calculate a viewable sphere around each unit as you render it and then after you''ve renderered all the units put the fog on top from a buffer of some kind? And you''d have to check what units to render aswell, if they''re in the fog or not...