Basically, the way I’ve always viewed godmoding is this. Godmoding, in my opinion, is the result of a player either bunnying, powergaming, or being omniscient. Those may be terms you’re more familiar with if you’re from another RP Forum. But just in case you aren’t, here’s a basic idea of what each of those terms refers to:
Bunnying - The act of undermining your opponent’s ability to properly handle the situation. Bunnying basically includes:
Role Playing your opponent's actions / reactions without their consent (exception, NPCs).
Forming closed attacks, i.e. explicitely stating that your opponent was hit (exception, again NPCs).
Performing an attack that, under normal conditions, cannot be blocked, dodged, or countered (exception, character’s weakened, in a bad position, or chooses to be hit).
Power Gaming - The act of doing something impossible (aka godly) to gain advatage. Power Gaming basically includes:
Role Playing an action or ability without explaining its origin and/or nature in ambiguous cases.
Role Playing actions or abilities that, under the circumstances would be impossible (e.g. blocking a powerful attack when severely injured, blowing up the planet, or taking down an entired armed army bare-handed).
Performing actions outside of a preset range with no apparent or explained connections (e.g. a Fire elementalist causing water to lash at an opponent).
Omniscience - The act of knowing all, or at least more than you should rightly be capable of knowing. Omniscience basically includes:
Knowing your opponent’s thoughts (exception, stuff like the Psi+ and Phi elements).
Knowing your opponent’s plans due to them being explained OOCly or through narrative (i.e. characters knowing what you know).
Knowing information about a character before it’s been revealed (exception, past experience that can be referenced or unless otherwise explained).
Describing characteristics of your opponent without their consent or before they’ve been revealed.
*Truth, if that's incorrect, please let me know so I can change it.
*NOTE - Generally, these only apply or are considered if your opponent is another player. Rules for NPCs tend to be more liberal, but don’t be surprised to hear people crack down on you if you bend / break the rules against NPCs either.Now, that’s not necessarily all you need to know about god-moding. Other specific rules come into play depending on what game you’re playing. For instance, the BA runs on the Element System, so doing things outside the capabilities of your element would be considerred GMing (under Power Gaming). For realms that use levels, having items, skills, spells, or abilities that are considered to be too powerful for you level would also constitute powergaming, as would having or wielding technology/magic considered inappropriate for the realm.
Generally, if there are more specifics than these, there will be stickies and/or guides written for the particular realm and it would do you well to read these. Other than that, experience and common sense (with the occassional kick in the butt from a mod) will help you dictate what is and what isn’t part of this concept known as God Moding.