When you have a power contingent on an enemy moving...

[Guyanthalas]

PHB pg. 285, Forced movment description

...
*No Opportunity Attacks: Forced movement does not provoke opportunity attacks or other opportunity actions.
...

You can argue hell and highwater if the extra damage granted by booming blade is an opportunity action, but it has a trigger and serves as an interupt (which are conditions of Opportunity action). DMing Morgan_Scott's game, we based our decision off of theorized intent, and I read the rules to back our decision.

 

[Nail]

You can argue hell and highwater if the extra damage granted by booming blade is an opportunity action, but it has a trigger and serves as an interupt (which are conditions of Opportunity action). DMing Morgan_Scott's game, we based our decision off of theorized intent, and I read the rules to back our decision.

So anything that has a trigger and serves as an interupt is an opportunity action?

 

[abyssaldeath]

PHB pg. 285, Forced movment description



You can argue hell and highwater if the extra damage granted by booming blade is an opportunity action, but it has a trigger and serves as an interupt (which are conditions of Opportunity action). DMing Morgan_Scott's game, we based our decision off of theorized intent, and I read the rules to back our decision.

No, opportunity actions are a subcategory of triggered actions. Opportunity action and interrupt actions are both triggered action types.

 

[Guyanthalas]

So anything that has a trigger and serves as an interupt is an opportunity action?

At face value without looking at other powers further I will say yes for now.

No, opportunity actions are a subcategory of triggered actions. Opportunity action and interrupt actions are both triggered action types.

Are you saying its not an opportunity action? If so, what defines an opportunity action?

*edit*
I'm not saying your point is invalid, I'm just saying that with the materials we have available to us currently there is a lot of interpretation to be made. Perhaps I'm making the judgement purely because I think its too powerful if otherwise implmented. I'm comfortable with that. As with Morgan_Scott's post, I think the idea behind the power is to create "stickyness" like other defenders.

 

[eamon]

Note that for instance the conditions sections speaks of...

Immobilized: You can't move from your space, although you can teleport and can be forced to move by a pull, push or slide.

Restrained: You can't be forced to move by a pull, push, or slide.
​

Suggesting that forced movement is just a a particularly (forced...) type of movement... The forced movement section doesn't contradict this, though it does contain a rule which might seem to say that at first sight:

Not a Move: Forced movement doesn't count against a target's ability to move on its turn. A target's speed is irrelevant to the distance you move it.
​

Common sense suggest that it might be tough, but that the fact that a creature happens to have been forced does mean it somehow doesn't need to carry the consequences of having moved. The "Not a Move" clause is already being rather nice when it comes to charms and the like, but that an acceptable simplification. In general however, a trap triggers whether you were forced onto it or whether you went there yourself. Perhaps the in-game reality isn't always simulated 100% accurately, but that's just an inherent trade-off. What should happen is a fighter footwork-lures an opponent away from the swordmage?

In cases of doubt, there is a fallback; the PHB says you can save to drop prone if you're being pushed off a ledge, and the DMG suggests this is more broadly applicable. So, if a particular combo is particularly non-sensical and abusive, this suggests a compromise: let the victim save to drop prone but avoid moving.

 

[DracoSuave]

Opportunity Actions are a class of actions just like Standard, Minor, and Immediate. Their restriction is you can only do one per player's turn, and not on your own turn, and all of them are Interrupts.

There's very few called out Opportunity Actions, but it is a very specific game term. One of those actions is Opportunity Attack, which is explicitly called out as an Opportunity Action. There's a couple powers which give you Opportunity Actions as well, and they explicitly use that terminology.

Triggers like this, however, are not Opportunity Actions. For example, if the Booming Blade victim were to walk away from you, they'd take the damage AND you'd be allowed an Opportunity Attack. If it were an Opportunity Action to deliver this damage, however, the victim would only get the damage, or the attack.

Also, this damage is not optional. You can't choose not to deal it, and Opportunity Actions are voluntary choices.

Besides, maximising the damage from Booming Blade is hard to do. It's not as easy as it would be for a Goblin Hexer to Stinging Hex someone amongst a soldier with a push ability--and this is perfectly legal and fair to do. The players have to work a LOT harder to exploit Booming Blade than you do to exploit the same rule... and you're supposed to be doing so with monsters.

 

[DracoSuave]

Are you saying its not an opportunity action? If so, what defines an opportunity action?.

First: It's not an action.

Second: Opportunity actions say on them 'This is an opportunity action.'

 

[abyssaldeath]

At face value without looking at other powers further I will say yes for now.



Are you saying its not an opportunity action? If so, what defines an opportunity action?

*edit*
I'm not saying your point is invalid, I'm just saying that with the materials we have available to us currently there is a lot of interpretation to be made. Perhaps I'm making the judgement purely because I think its too powerful if otherwise implmented. I'm comfortable with that. As with Morgan_Scott's post, I think the idea behind the power is to create "stickyness" like other defenders.

Page 268 of the PHB defines what an opprotunity action is.

Triggered Action Types Two action types—opportunity actions and immediate actions—require triggers. A trigger is an action, an event, or an effect that allows you to use a triggered action. (Some powers require a trigger but are free actions or aren’t actions at all.)

This header tells you that opportunity actions and immediate action are separate things.

 

[Hypersmurf]

Could it be that the moving away referenced there must take place during the enemies turn? ( I think a close reading of the text confirms this interpretation.)

Of course, I don't really see how it could be read otherwise.

However, I'd say that the power's movement-penalizer only works on the enemy's own turn...

So the target of Booming Blade can avoid the effects by readying an action to move, so that his movement occurs when it is not his turn?

-Hyp.

 

[DracoSuave]

Pretty much, Hyp. Of course, that costs him a Standard Action, so it's still in the benefit of the Swordmage. Lose your attack to get out of dodge? Sure. That's a good deal.