Determining distance for Dimension Door.

[Tiber11]

How does a player determine how far away something is to d-door to it/inside it?

For example, there is a building with a bunch of guards patrolling outside it and the player wants to d-door inside the building to surprise its occupants. The player has not been inside the building, another party member has seen inside.

Let's say it looks about 500 feet away, but the player is actually standing 505 feet away from the outer wall, which is 5 foot thick and the party of 4 is standing in a 10 foot square formation with the caster in a front square. The building is 40 foot on each exterior side. My understanding of the rules is that if the party wants to safely d-door into the building, the caster would need to know that the distance is at least 520 feet, but not greater than the far wall at 545 feet.

How would the player be able to determine the specific, straight line, distance to cast? Is that building 500 feet away? 600? 650?

My players are wanting to use Dimension Door to sneak around and repeatedly surprise an enemy encampment. Dropping in from outside the perimeter walls to wreak havoc.

Teleport at least gives a percentage chance of a mishap. How to determine if they land inside the building or outside when the exact distance can not be known?

[Fuzzy-Wuzzy]

I don't see any realistic/reasonable way to determine distance that precisely from that far away, nor any reason they ought to be able to. They'll have to guess and live with the consequences.

Unless you're specifically trying to support this tactic, in which case IMHO it's within your discretion to rule that "10' farther than that wall I can see" is an acceptable d-door target.

[Blymurkla]

»You always arrive at exactly the spot desired – whether by simply visualizing the area or by stating direction«

Do you need an exact distance? Can't you just see the house, visualise the inside of it and then dimension door.

[Pizza Lord]

The spell can be used to either a stated distance, to a visualized one, or an obvious one (such as the other side of a door.) I don't let players instantly know distance just like they were some computer.

If a caster says they want to appear 400 feet straight up, they appear 400 feet straight up. Likewise, if the caster wants to appear inside a building, they can try to appear on the other side of a door or wall. Most people have a decent ability to gauge walls' and doors' thickness (walls less so than doors, of course.) Most walls and doors aren't 5 feet thick though, so it's normally a moot point.

It's not a huge deal. If they mess up, say they think a wall is 2 or 3 feet thick but it's 5 feet and they try and just appear on the other side... they take 1d6 damage and are moved to the nearest safe space within 100 feet. This is probably going to be where they wanted to be. Only if the building was completely solid would they fail (and would appear on the outside of the wall, since that's the next closest.)

Even if there isn't a free space within 999 feet... that's just an extra 2-12 damage and that is almost an unheard of situation. You would have to be hugely mistaken about the destination to not have an open space within 1,000 feet. It practically takes a 20th-level caster gets over that range so you're pretty much guaranteed to at least end up back in your starting point if everywhere else around you is solid rock.

So... if they clip the wall, 1d6 damage and they're inside. If they aim further, thinking the walls are thicker and end up in a table or bookshelf... 1d6 damage and they're inside. Either way they've probably surprised whoever's in there (but that doesn't mean they aren't surprised either unless they know someone is in there as well who might react faster than them.)

[Mark Thomas 66]

My GM let me do it with an Int check or high Knowledge geography. That being said My Magus is at Int 24 so......

[Garbage-Tier Waifu]

This is why scrying is important, people.

Either way, it's entirely on the guesswork of a player as to whether they can dimension door onto a space. If they have seen the space, they should be able to determine the distance from their current space to their target. A character should also know the dimensions of a building from observation and any observable space from any entrance or window they can see. They cannot, however, know anything about a space they cannot observe but nothing stops that character from targetting a space either way.

Throwing a spanner into targetting like that will require sweeping changes to spells that don't require line of effect. These spells generally already punish miscalculation, so I don't think there is anything that needs to be done.

[Tiber11]

Fuzzy-Wuzzy wrote:

I don't see any realistic/reasonable way to determine distance that precisely from that far away, nor any reason they ought to be able to. They'll have to guess and live with the consequences.

Unless you're specifically trying to support this tactic, in which case IMHO it's within your discretion to rule that "10' farther than that wall I can see" is an acceptable d-door target.

I'm not supportive! It's becoming annoying as a DM. I was kind when they tried it the first time, now they are abusing it and the module does not give me a lot of CR/creature viable options to counter. :)

I wanted a way to determine exactly where they end up when they are trying to guess the distance!

[Brother Fen]

Tiber11 wrote:

How does a player determine how far away something is to d-door to it/inside it?

For example, there is a building with a bunch of guards patrolling outside it and the player wants to d-door inside the building to surprise its occupants. The player has not been inside the building, another party member has seen inside.

Let's say it looks about 500 feet away, but the player is actually standing 505 feet away from the outer wall, which is 5 foot thick and the party of 4 is standing in a 10 foot square formation with the caster in a front square. The building is 40 foot on each exterior side. My understanding of the rules is that if the party wants to safely d-door into the building, the caster would need to know that the distance is at least 520 feet, but not greater than the far wall at 545 feet.

How would the player be able to determine the specific, straight line, distance to cast? Is that building 500 feet away? 600? 650?

My players are wanting to use Dimension Door to sneak around and repeatedly surprise an enemy encampment. Dropping in from outside the perimeter walls to wreak havoc.

Teleport at least gives a percentage chance of a mishap. How to determine if they land inside the building or outside when the exact distance can not be known?

The caster is supposed to know where they are going, IE: having been there before.