Tutorials Archive | 4/14/2011
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Tutorial: Terrain Powers
By Mark Monack

Terrain can add much to your game and it can create more dynamic encounters in the form of hazards, traps, terrain effects, and other features. This article deals specifically with terrain powers—a system described in the Dungeon Master’s Guide 2 (pages 62–63). Terrain powers are physical elements within an encounter area that have the potential to be incorporated into a fight. Although some players and DMs might feel uncomfortable using powers that do not appear on their character sheets or statistics blocks, terrain powers can add an incredible cinematic quality to fights. Essentially, these powers can help you transcend the grid and allow the heroes to more fully interact with their surrounding world.

For DMs looking to create more interactive encounters, the following tutorial provides techniques for designing, improvising, and using terrain powers.

Set the Mental Stage

When incorporating terrain into an encounter, it helps to have a mental image of your encounter area. Imagine the area devoid of any heroes and villains. What stunts can you envision occurring there during the encounter? Jot down notes as to how these stunts might appear, and how they might translate into powers.

For example, you might anticipate a brawl occurring in a tavern (as is often the case). Brawlers might slide opponents across the bar. People might hide behind upturned tables for cover. The entire tavern might be set ablaze by a stray candle. Include these elements in your encounter.

Distinguishing Terrain Powers

It is important to distinguish terrain powers from other game elements. Unlike terrain traits (which automatically impose conditions), terrain powers require an action to use. And unlike traps and hazards (which frequently target the heroes exclusively), terrain powers are intended to be useful to both the heroes and their adversaries. Because either side can use terrain powers, they do not impact the encounter’s XP budget; however, you must ensure that the terrain is in fact equally useful to all sides.

For example, you might include a rug that can be used to trip an opponent. If placed near the center of the combat area, either the heroes or villains could use the rug. The rug might affect the battle without ever being used if the heroes work to avoid having the rug literally pulled out from under them.

In addition to being useful to heroes and villains alike, terrain powers should also be useful to different types of characters. Every player enjoys dealing damage to and placing conditions on the enemy. Strikers, brutes, and skirmishers, however, prefer terrain powers that allow them to be more mobile and avoid obstacles. Leaders, controllers, and artillery prefer terrain powers that afford them cover. Defenders and soldiers might prefer terrain that hampers the enemy’s movement. While you need not include terrain for every character in every encounter, try to vary the terrain types across adventures, so that everybody has a chance to enjoy them.

For example, in the bar brawl, you might place tables for the ranged and area attackers to overturn and use for cover. The bar might allow defenders to slide opponents away from their allies. Controllers and strikers might force opponents into mounted antlers and horns on the walls that deal extra damage.

The Mechanics of Terrain Powers

Designing terrain powers is similar to designing creature powers. Like creature powers, terrain powers have a frequency (at-will, recharge, or encounter), an action type (standard, move, minor, free, or triggered), and an effect. Some terrain powers also require attack rolls. If a terrain power imposes a condition, ensure that the condition is appropriate to the party’s level (see the “Terrain Conditions” sidebar). If a terrain deals damage, the power’s median damage should rarely exceed half the level of the character using the power.

Designing terrain powers requires a DM to consider that power’s frequency, action type, attack roll, and effect.

  • Frequency: Terrain powers should accent an encounter, not dominate it. Most terrain powers should be usable only once an encounter (even at-will terrain powers are—given the situation—typically used once an encounter at best; a hero is not likely to slide down a banister, then climb back to the top of the stairs to slide back down again). Using it only once per encounter heightens an encounter’s drama as the heroes and their opponents compete to see who uses it for their side.

  • Action: The action assigned to a terrain power should be commensurate with the power’s effect. The more potent the effect, the more costly the action type needed to use it. Generally, terrain powers should require a move or minor action to encourage players to engage the terrain without having to forego their character’s usual powers. Standard action terrain powers should be reserved for potent effects.

  • Attack: A terrain power that does not have an effect on an enemy should not require an attack roll or a skill check to use. Characters should be able to use powers that allow them to avoid obstacles, gain cover, or otherwise benefit themselves or their allies without arbitrary threshold rolls of the dice. Reward them for using the terrain.

  • Option: For terrain powers that do attack an enemy, you can choose to go with a standard “Level + 3” attack. You might also consider assigning a skill check opposed by the target, rather than a traditional die roll opposed by a target’s defense. Enemy defenses assume that the heroes use weapons with appropriate enhancement and proficiency bonuses that terrain powers lack. An opposed skill check also captures the improvisational feeling of relying on the objects and terrain around you rather than a character’s own powers.

  • Complexity and Utility

    Unopposed skill checks, most commonly using Athletics or Acrobats, can limit who uses a terrain power to only those trained in such skills when you’re trying to encourage heroes of all skills to make use of the terrain. Also, every roll you impose on a power increases the complexity of that power. Players don’t want complicated powers with minor effects. If something is going to be complicated, you want a big bang for that effort, and terrain powers shouldn’t be that complicated.

    If you require an unopposed skill check on terrain powers, I’d suggest an easy DC, rather than moderate. If the DCs are moderate or worse, players will likely ignore the terrain powers and use their tried and true minor and move actions instead.

  • Effect: Terrain powers should impose either damage or a condition, but not both. These powers should not overshadow the characters’ own powers. For example, you might create a chandelier that can be released to fall on a target, dazing it until the target spends a move action to get free. Normally, such an attack would require an attack roll. Instead, allow the power to work automatically. Since the terrain power’s effect is obvious, the challenge is not in hitting the target, but instead in manipulating the target onto the square into which the chandelier will fall. Approaching the matter in this way allows characters to used forced movement to great effect.

Terrain powers can mirror character development. As the heroes encounter the same terrain at various tiers of play throughout their careers, they might observe that they can do more with that terrain. As the hero’s level increases, a terrain power could be used with a minor action rather than the move action required at lower levels. A terrain power can also impose more damage or a more severe condition for higher level characters.

Terrain Conditions

Epic Standard: Dominate, stun, or petrify
Paragon Standard or Epic Move: Blind, daze, immobilize, restrain, or weaken
Heroic Standard, Paragon Move, or Epic Minor: Grant combat advantage, allow a mark, or penalize a defense by up to –2
Heroic Move, or Paragon and Epic Minor: Avoid intervening obstacles during a move; grant concealment and/or cover; knock prone; push, pull, or slide enemy up to 4 squares; deafen; or deal level-appropriate ongoing damage
Heroic, Paragon, and Epic Minor: Add a damage type to an attack or allow a 1-square shift

Encouraging players to use terrain powers that the DM devises for an encounter—and even to improvise their own—is not an easy task. A DM can encourage players to think more about manipulating terrain. The most obvious method is to tell players about opportunities to use terrain powers. When they enter an encounter area, tell the players what some of these terrain features can accomplish if properly manipulated.

“As the tavern-goers stand and draw their weapons, you quickly assess the scene. The bar is slick and wet with drink. You could slide a grabbed foe down its length, or set it aflame. The tables could be overturned for cover. Above the bar, a heavy woolen tapestry could be dropped on people by releasing the thick cord that loops over the rafters to a peg on the far side of the room. The swinging doors into the tavern could be kicked into people to knock them prone. Some of the horns and antlers mounted on the walls are positioned so that if you were to push or slide opponents against them, they might be impaled.”

A more effective technique is to show terrain being used. When enemies use terrain against the heroes, the players might want to use that same terrain against their enemies. At a minimum, the players might feel the need to use the terrain if only to keep up.

“An orc kicks the swinging doors open, causing Reginald to sprawl forward. ‘So these are the heroes who messed with my nephew,’ he says disparagingly. He steps forward into the middle of the room, followed by four companions. One of them, you notice, stands on the throw rug before the fireplace.”

The best method for encouraging players to improvise terrain powers is to say “Yes” whenever they suggest them. When your players want to collapse a tunnel to hinder their enemies from escaping, let them try. Improvising a terrain power is no different from designing one. As set forth above, the terrain power should require a move or minor action. Use the “Terrain Condition” section above to determine what conditions are appropriate based on the heroes’ levels. Limit the duration of any conditions to no later than the end of the target’s next turn. And remember that your group’s enemies can also implement any terrain power devised by your players.

Sample Terrain Powers

Banister
At-Will Terrain
A long, polished marble banister runs alongside the staircase.
Move Action (Heroic)/Minor Action (Paragon or Epic)
Check: Acrobatics check (easy DC) to slide from the top to the bottom of the banister and land safely at the end of the banister.
Success: You slide from the top to the bottom of the banister, even if enemies occupy the squares on the staircase. This movement provokes opportunity actions from those on the staircase. You land in the square at the end of the banister.
Failure: You fall prone in the square at the end of the banister.
Effect: The banister grants cover to those on the staircase.

Bar Top
At-Will Terrain
A 20-foot long bar is wet with drink, and it smells of strong alcohol.
Move Action (Heroic)/Minor Action (Paragon or Epic)
Check: Athletics vs. Acrobatics to slide a creature along the bar.
Success: You slide the grabbed creature up to 4 squares to any square adjacent to the bar. The target must succeed on a saving throw, or it falls prone.
Effect: The first attack with the fire keyword that targets a creature adjacent to the bar causes the bar top to ignite. Once ignited, until the end of the encounter, any creature that starts its turn adjacent to the bar or enters a square occupied by the bar takes 5 fire damage (increase to 10 fire damage at paragon tier and 15 at epic).

Cracked Drainpipe
Single-Use Terrain
A drainpipe ahead of you leaks, forming a large puddle underneath it. Given the amount of water you hear flowing through the pipe, taking advantage of the existing crack in the pipe might unleash a powerful torrent of water.
Minor Action
Requirement: You must have one hand free.
Check: To break the pipe without being affected by the resulting stream of water, make a Dungeoneering check (easy DC).
Success: The pipe bursts, causing a high-pressured stream of water to shoot out and hit a creature of your choice.
Target: One creature in a close blast 1 adjacent to the broken section of pipe.
Attack: Level + 3 vs. Reflex
Hit: The target is pushed up to 2 squares and falls prone.
Failure: The pipe does not burst.

Hearth
At-Will Terrain
A large fire blazes in the center of the room. Throwing an object into the hearth might scatter hot cinders into the air.
Standard Action (Heroic or Paragon)/Move Action (Epic)Zone
Check: You throw an object into the hearth from up to 5 squares away (no roll required).
Effect: Cinders scatter into the air in a close blast 1, creating a zone that lasts until the end of the encounter. Treat the zone as obscuring terrain. Any unattended flammable objects in the zone ignite. If you place a nonflammable object into the hearth, that object gains the fire keyword and can cause fire damage if it is used in an attack until the end of your next turn.

Pool of Knowledge
Encounter Terrain
A large pool sits in the middle of the room. Flowing through the water, the spirits of dead sages cry for release, offering their knowledge, but possibly consuming your soul.
Standard Action (Heroic)/Move Action (Paragon)/Minor Action (Epic)
Check: History check (easy DC) to recall a specific dead sage while touching the water in the pool.
Effect: You touch the water in the pool. Until the end of the encounter, all skill checks you make take a –2 penalty. If an attack with the necrotic keyword includes the pool in its area of effect, all targets hit by that attack take extra necrotic damage equal to one-half the level of the attacker.
Success: If you succeed, choose one skill. The next time you roll for that skill before the end of the encounter, treat the roll as a natural 20.

Rug
Encounter Terrain
A gaudy throw rug tries to cover up cracks in the floor.
Move Action (Heroic)/Minor Action (Paragon and Epic)
Requirement: You must have one hand free.
Check: Athletics check (easy DC) to pull the rug out of its space.
Success: You pull the rug out of its space.
Target: Each creature standing on the rug
Attack: Level + 3 vs. Reflex
Hit: The target falls prone.

Table
Encounter Terrain
A stout oak table sits unattended.
Move (Heroic)/Minor (Paragon and Epic)
Check: Athletics check (easy DC) to overturn the table.
Success: You overturn the table.
Target: Each creature on the table
Effect: A target must make an Acrobatics check (moderate) or fall prone in a random unoccupied space adjacent to the table. The table grants cover.

Vinaceous Fungus
Encounter Terrain
This enormous mushroom, which is the color of burgundy wine and a cousin of the more common violet fungus, is dangerous when casually brushed—but useful to those who know how to manipulate it.
Standard (Heroic)/Move (Paragon)/Minor (Epic)Poison, Zone
Check: Athletics check or Nature check (easy DC) to cause the mushroom to release its spores in a way that does not affect you.
Success: The mushroom’s spores puff out in an close blast 2, creating a zone that lasts until the end of your next turn. Any creature in the zone gains partial concealment.
Target: Each creature in the blast
Attack: Level + 3 vs. Fortitude
Hit: 5 + one-half level poison damage.
Effect: While the zone persists, any creature takes 5 poison damage each time it leaves a square of the zone (increase to 10 poison damage at paragon tier, and 15 at epic).

Sample Terrain Card

Name: ____________________ Frequency: _____________ Terrain
Description:

___________ (Heroic)/___________ (Paragon)/___________ (Epic) ___________
Keywords
Requirement:
Check:
Effect:
Success:
Target:
Attack:
Hit:

About the Author

Mark "wrecan" Monack is a freelance writer who has been playing D&D since a bout of the chicken pox quarantined him with nothing but rulebooks for company. Since then, he has been playing and writing about RPGs, including designing a tabletop version for the Alliance, the first live action roleplaying game. You can read more at his blog, Unearthed Wrecana. He would like to thank his wife, children, and Rob's Econ Study Group for their unflagging support.