How, as DMs, do you handle terrain powers during combat?
Do you simply describe the features of the area without any information about how the terrain can be used as a power? Do you hint at the terrain powers without specifically outlining their mechanics (e.g., "The alchemist's lab shelves look rickety, and you can probably unleash all sorts of havoc by knocking them over.")? Do you ennumerate terrain powers explicitly and describe their mechanics before combat begins?
Furthermore, do you always predesign such powers, or do you incorporate them as a variation of the character stunt when the PC comes up with an innovative way of utilizing terrain?
1) Anything battlefield elements that can be interacted with (either via stunting, force moving into hazards/traps or hindering/challenging/difficult terrain) always have their mechanical components laid bare to the players. Minions are Minions. Swarms are Swarms. HP and Defenses are made clear. So for Terrain Stunting that I put in at the beginning of battle, look at my Skill Utilities thread. After the fiction is made clear, this exact info would be given to players:
Obelisk of Attraction
Limited-Use Terrain - Arcane, Charm
Standard Action - Close Burst 10
Check: Arcana check (high DC) to activate the Obelisk
Success: The Obelisk attacks.
Target: Each enemy in the burst.
Attack: Level +3 vs. Will
Hit: The target is pulled 5 squares toward the Obelisk and suffers Obelisk's Attraction (save ends); The target cannot move into squares that would place it further away from the Obelisk.
2) Sometimes players will initiate the terrain element that can be stunted with. A Druid might say something like "Ok, we're at the top of a ridge with loose rocks and boulders strewn across a fairly steep slope? I want to see if I can summon the primal spirits of the wind and trigger a rock-slide on our enemies below!" Then we quickly agree upon:
Avalanche! - Limited-Use Terrain
Standard Action - Ranged Burst 2
Check: Nature (high DC) with Chill Wind
Success: The scree and boulders cascade down the slope
Target: Each creature in the burst.
Attack: Level +3 vs. Fortitude
Hit: 2d10 +3 damage and you slide the target 3 squares or knock it prone.
Miss: Slide the target 3 squares.
Effect: The ground becomes difficult terrain.
3) Probably 80 % of the content of my games is adlibbed in the moment. Terrain Stunts are trivially easy to adjudicate or conjure out of thin air.
a) Is this something that can be repeated multiple times in the combat or something that gets used up when interacted? High At-Will Damage Expression (I always use High for stunts) or Limited-Use Damage Expression.
b) Which skill applies for success, what DC (A-W are often Medium and L-U are often High), and what is complication/cost of failure (Healing Surge worth of damage, or some sort of control effect UEoYNT).
c) AoE? Subtract 25 % of expression budget.
d) Tier-Equivalent Control Rider? Subtract 12.5 - 25 % of expression budget (depending on if weak AW or legit E rider).
e) Miss and/or Effect? Subtract 12.5 % - 25 % of expression budget.
Done.
