Do spells that provide concealment provide it past the targeted area?

[holywhippet]

Spells like fog cloud and darknesss conceal or obscure the area they are in. Does that only apply to creatures/objects inside of the area, or should I assume anything that if two creatures are on directly opposite sides of such an effect they can't see each other either?

[Man_Over_Game]

Fog Cloud and Invisibility refer to things being Heavily Obscured. Obscuration effects are in regards to sight. Since "Line of Sight" is...well, dependent on actual sight, abilities that provide area obscuration (Fog Cloud, Darkness) would block any vision between the two people. The only reason that the players can perceive things beyond those elements is the fact that most of us play with a battle map. Using the "theatre of the mind" is a bit more accurate in these regards, since the DM would just say "You can't see anything past the Fog Cloud, but you still hear movement beyond it".

[terodil]

Spells like fog cloud and darknesss conceal or obscure the area they are in. Does that only apply to creatures/objects inside of the area, or should I assume anything that if two creatures are on directly opposite sides of such an effect they can't see each other either?
Darkness is special in that it prevents all light from going in, out, and through, so yeah, you can't see anything beyond, but uncovered by it either.

I wouldn't say that you could normally see through fog either, though that's more of a physical effect of light scattering rather than the magical absolute impregnability of Darkness. I'm not sure how infravision or the like would be affected.