D&D 5E Roper Tactics

[silentbob1]

Hello,

I am creating an encounter in a cavern using a roper that is hanging from the ceiling. The roper is 30' up and in the middle of the 45'x60' cavern.

I know that the roper's tendrils have a 50' reach, but I don't know how to take into account the 30' of height to get a correct range. Could the roper reach a medium sized creature on the ground 20' or 30' away?

 

[Croesus]

If I understand correctly, the roper is 30' up, and 30' from any edge of the cavern (60' diameter = 30' radius).

The formula for calculating the hypotenuse is Square Root of [Height (squared) + Length (Squared)]. (Not sure how to type mathematical symbols...)

So the max distance is the square root of [(30x30) + (30x30)]. Square root of 1,800 is approx. 42.4 feet. So, yes the roper can reach everyone.

Solving for the 50' reach, the roper would just be able to reach everyone if the distances are 30' and 40', length and height, or vice versa. Less than or equal to 30'x40' and you can be certain it can reach anything in the area.

 

[LordEntrails]

An easier way, in this case is that their is a "magic triangle" called the 3/4/5 triangle. It is a right triangle and the length of the sides are 3 and 4 and the length of the hypotenuse (side opposite the right angle) happens to be 5 units long.

You can multiple this triangle by ten which just happens to be perfect for your situation; 50 foot reach (i.e. the hypotenuse length) and a 30 foot height. Meaning the diameter of the circle that is in range for your roper is 40 feet. Lucky you

 

[Eltab]

Simpler math: (distance of reach across ground) = (total length of tentacles) - (height above ceiling). In other words, the roper drops all its tentacles straight down, and reaches out across the floor from there.
Not as realistic, but easy to calculate. It can reach 20 feet out from the square it is above. It can cover a space 40 feet across. This gives the PCs a way to escape it. They can (just barely) hide along one nearer edge of the cavern, and there is more space at both ends.

 

[Croesus]

50 foot reach (i.e. the hypotenuse length) and a 30 foot height. Meaning the diameter of the circle that is in range for your roper is 40 feet. Lucky you

Did you mean radius?

 

[LordEntrails]

Did you mean radius?

oh yeah

 

[Sorcerers Apprentice]

Since moving diagonally across squares still only cost 5 feet of movement per square in 5E, it follows that in the game physics √2 = 1. As such whether or not a roper is on the ground or 30 feet above makes no difference to its reach at ground level.

 

[LordEntrails]

Since moving diagonally across squares still only cost 5 feet of movement per square in 5E, it follows that in the game physics √2 = 1. As such whether or not a roper is on the ground or 30 feet above makes no difference to its reach at ground level.

Unless the DM decides to;
A) use the optional distances rule from the DMG, or
B) use common sense

 

[jgsugden]

If you like props: 10 inch string.