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View Full Version : The Combat Reformation: Cover and Concealment



Vadskye
2014-02-06, 01:08 PM
Why It Needs Fixing
Traditionally, cover is defined as "an obstacle or effect which blocks line of effect", and concealment is defined as "an obstacle or effect which blocks line of sight". (I'm paraphrasing here.) This is fairly straightforward, though poorly explained; in my experience, even experienced players are often confused about the difference between cover and concealment. However, cover provides a bonus to AC, while concealment provides a miss chance. This makes very little sense.

Miss Chance Logic
A miss chance has a specific implication: "No matter how skilled you are, you can still miss." Dim lighting and shrubbery should not impose a miss chance; those conditions merely reduces the size of the target the attacker can aim at. The shot is more difficult to make, but a sufficiently skilled character could still hit every time. Therefore, concealment should not use a miss chance.

What Deserves A Miss Chance?
Miss chances should be reserved for situations where hitting or missing is beyond the attacker's control. An archer who makes a perfect shot can still miss if something got in his way after he shot the arrow. That means moving obstacles impose a miss chance.

The Solution Active cover is caused by a mobile obstacle - almost always a creature. Active cover imposes a 20% miss chance. An attack that misses because of this miss chance is made against the intervening obstacle instead.
Passive cover is caused by static obstacles like walls, trees, and so on. It grants a +4 bonus to AC and a +2 bonus to Reflex saves.
Concealment is caused by dim lighting and obstacles that only block line of sight. It grants a +4 bonus to AC.


Only passive cover blocks attacks of opportunity. Passive cover and concealment can be used to hide, but not active cover.

Implications
There is no penalty for shooting into a mass of enemies. If you miss because of the miss chance, you simply strike someone other than your intended target. In addition, it is possible to accidentally strike your allies by firing recklessly through them!

This change could be integrated into other aspects of the system in interesting ways. For example, using Aid Another to protect an ally could grant them active cover, and any attacks that miss from that miss chance would be made against you instead.

Note about the "Combat Reformation":
The Combat Reformation is a series of fixes and adjustments I will be making to D&D's core combat system. Based on feedback from the Spell Reformation, each change will be designed to be modular, so you can use any one of the changes without using the others.
Other elements of the Combat Reformation:
Cover and Concealment (http://www.giantitp.com/forums/showthread.php?329767-The-Combat-Reformation-Cover-and-Concealment)
Attacks of Opportunity (http://www.giantitp.com/forums/showthread.php?338630-Attacks-of-Opportunity-(The-Combat-Reformation))