## dnd 5e – Are there rules for falling in water vs. diving vs. just jumping in for various depths of water?

Just realized that in DMing 5e I have unconsciously used a falling-in-water rule-of-thumb that I inherited from somewhere (maybe 2e or AD&D or maybe even Pathfinder). The ruling I’ve been using is as follows:

• No damage for 20 feet of falling.
• Half-damage next 20 feet.
• Normal damage beyond that.

Realizing there should be a Strength (Athletics) for “swimming” (in context, “diving”) to take even less damage with a proper dive in sufficiently deep water, I started to look for specifics on that. Am I just missing it somewhere? (Also didn’t find it searching this stack.)

Are there clear 5e rules for both jumping and diving in water of various depths?

## dnd 5e – Are there rules for falling in water vs. diving vs. just jumping in for various depths of water?

Just realized that in DMing 5e I have unconsciously used a falling-in-water rule-of-thumb that I inherited from somewhere (maybe 2e or AD&D or maybe even Pathfinder). The ruling I’ve been using is as follows:

• No damage for 20 feet of falling.
• Half-damage next 20 feet.
• Normal damage beyond that.

Realizing there should be a Strength (Athletics) for “swimming” (in context, “diving”) to take even less damage with a proper dive in sufficiently deep water, I started to look for specifics on that. Am I just missing it somewhere? (Also didn’t find it searching this stack.)

Are there clear 5e rules for both jumping and diving in water of various depths?

## equipment damage – DSLR in sand and salt water

Doing a stop-motion by the sea, the camera and tripod got overrun by a wave and submerged in salt water, and then on sand. From reading this forum thread, this one, and watching this video, I am doing the following:

• a freshwater bath (how long?)
• leaving to dry in the fridge for 3 days
• taking apart the whole camera
• cleaning the components with a cotton swab and alcohol
• putting it together again

Does this seem appropriate, or would another course of action offer better chances?

## mesh – Smoother jelly / water effect on an image

I’m trying to achieve a jelly / water surface effect. I’d like it to be a bit smoother. Here I am taking a triangulated rectangle and perturbing all points by a little random noise for each frame. This warps the polygons and stretches the texture so it looks like it’s a turbulent liquid surface:

``````img = ExampleData[{"TestImage", "House"}];
mesh = TriangulateMesh@Rectangle[{0, 0}, {1, 1}];
coords = MeshCoordinates[mesh];
cells = MeshCells[mesh, 2];
texture = Texture[img];

Table[With[{newcoords = coords + 0.01*RandomPoint[Disk[], Length[coords]]},
Rasterize[
Graphics[{texture,
GraphicsComplex[newcoords, cells,
VertexTextureCoordinates -> coords]}]]
], {30}] // ListAnimate
``````

To make this better and less jumpy I think I need to accumulate the small random disturbances of the coordinates of the mesh. But I don’t want any point on the mesh to drift and deform its polygon so much over time that it becomes highly distorted with extreme self-intersections. Any ideas how I can do this and not push up computation time?

## What kind of artistic variables are useful for water?

I have tried to implement water by solving the shallow water equations, but it is very complicated, computationally expensive and hard to get right (especially near coastlines) so I was wondering if I could approach the problem from a different direction.

What kind of variables would one want to have to steer how water behaves/looks? I have thought of:

• wind/water velocity (for visual feedback and boat mechanisms or something)
• terrain (so it can flow down, creating waterfalls and such)
• ripples (to make satisfying visuals and maybe cannon mechanics or something)

Do you know more common use cases for water? Maybe I can get away with some model that can churn out beautiful visuals (maybe deep learning based?) instead of solving pdes that diverges for seemingly no reason….

## health – Finding drinkable water while travelling

In some places like India, you can order “boiled water” even in a restaurant – they know visitors may have issues with water safe for locals. It should get you boiled and cooled water, or else options for water that is safe for visitors – filtered or otherwise purified water – since they would guess that’s why you’re asking. It should work to get your point across, and they can let you know what options are locally available. Even if it isn’t a known thing where you’re traveling, it should get you safe water once they figure out you really want your water boiled.

In other places you can order as a drink something like hot water with lemon, a different context for the same precaution – boiled water. This may be cheaper than bottled water, since tap water is cheap and need only be heated, though no guarantees.

Another possible alternative is fruit – fresh squeezed juice (it must be undiluted, so very fresh and/or prepared before your eyes) is generally safe, and in some countries widely available. Even if not, eating some fruit can help you need less water overall as you get moisture from the juices.

ps – remember to be wary of local ice, it can be made from not-visitor-safe water.

## dnd 5e – Water Elemental grappling a Huge creature, does it take damage from Whelm’s second paragraph?

The Water Elemental(Basic Rules, 158) stat blocks states with my empahsis:

Each creature in the elemental’s space must make a DC 15 Strength saving throw. On a failure, a target takes 13 (2d8 + 4) bludgeoning damage. If it is Large or smaller, it is also grappled (escape DC 14). Until this grapple ends, the target is restrained and unable to breathe unless it can breathe water. If the saving throw is successful, the target is pushed out of the elemental’s space.

The elemental can grapple one Large creature or up to two Medium or smaller creatures at one time. At the start of each of the elemental’s turns, each target grappled by it takes 13 (2d8 + 4) bludgeoning damage. A creature within 5 feet of the elemental can pull a creature or object out of it by taking an action to make a DC 14 Strength check and succeeding.

There is no option for grappling a Huge, just that if it is large or smaller it is grappled. Huge and Gargantuan creatures are not valid targets for this grappling effect and subsequent damage. And the 2nd paragraph of the Whelm action still contains the requirements on size.

## Grappling outside of Whelm

While there are rules around grappling creatures one size larger, those rules don’t apply to Whelm’s actions. Only the requirements within the Whelm action are relevant to determining how the Whelm works.

Meaning that even if they could grapple a Huge creature (which may be up to a DM to determine), they can not Whelm it.

## dnd 5e – Can the spell Water Walk help in the fight against a Water Elemental?

The spell Water Walk:

grants the ability to move across any liquid surface–such as water, acid, mud, snow, quicksand, or lava–as if it were harmless solid ground (creatures crossing molten lava can still take damage from the heat). Up to ten willing creatures you can see within range gain this ability for the duration.

If you target a creature submerged in a liquid, the spell carries the target to the surface of the liquid at a rate of 60 feet per round.

Water Elementals, thanks to their Water Form, ‘can enter a hostile creature’s space and stop there’ then use their ability ‘Whelm’ which states:

Each creature in the elemental’s space must make a DC 15 Strength saving throw. On a failure, a target takes 13 (2d8 + 4) bludgeoning damage. If it is Large or smaller, it is also grappled (escape DC 14). Until this grapple ends, the target is restrained and unable to breathe unless it can breathe water. If the saving throw is successful, the target is pushed out of the elemental’s space.

The elemental can grapple one Large creature or up to two Medium or smaller creatures at one time. At the start of each of the elemental’s turns, each target grappled by it takes 13 (2d8 + 4) bludgeoning damage. A creature within 5 feet of the elemental can pull a creature or object out of it by taking an action to make a DC 14 Strength check and succeeding.

Could Water Walk, by RAW, assist my PCs in their fight against a Water Elemantal?

Specifically:

1. Could the benefits of Water Walk help prevent a target from being whelmed?
2. Once already whelmed, could the benefits of Water Walk help a target escape from within the confines of a Water Elemental’s grapple?

## uk – Save pitcher filters, what filters chemicals and metals from water, for separated British taps without space around it?

I wholly agree with the other answer which says that you could just get quality tap water from the staff or something like that.

However, for this answer I’m doing something I often do, which is accept the premise of the question itself, which says “I want a device to remove the following substances from water.” I am assuming (wrongly or rightly) that is a justified premise, and answering that.

Considering the substances that need to be removed, I’d say that this can not be accomplished by simple filters. As references for this statement, see answer 1 and answer 2.

You need either a distiller or reverse osmosis.

Incidentally, both these methods also remove pathogens, so there will be no need to additionally boil the water.

Reverse osmosis accomplishes this by pumping water through a membrane with very tiny holes. A good RO system removes everything you are talking about in the question. Here’s another answer in which I mention an RO system that is portable and can be connected to the tap through a hose, eliminating the space concerns.

You mention chlorine in OP. Please note that the higher the chlorine level, the more of a strain it will be on the membrane of the RO system. (For normal, municipal water chlorine levels, it’s not a problem, though.) But the higher the levels of chlorine, the more often the membrane will have to be replaced.

Distillation works by creating steam and collecting the steam as water. Since none of the chemicals or pathogens you mention will evaporate in the steam, they will be eliminated in the distillation process. Here’s a related answer in which I describe distillation in further detail. With most distillers, you manually pour the water into the distiller using a jug or something like that. Thus, the space is not a problem there either.

Please note that distillation is quite energy inefficient compared to RO. It uses a relatively high amount of electricity, whereas RO does not.

## complexity theory – Algorithm for optimizing water filling

There are some cups of possibly different capacities. Each cup has a label which is a subset of $${1,2,dots,n}$$. You have a certain amount of water which you can use to fill the cups. At the end, let $$x_i$$ be the total amount of water in cups with label $$i$$. You want to maximize $$min(x_1,ldots,x_n)$$ (and subject to that, maximize the next smallest number among them, and so on). How can you do that?

For $$n=2$$ it is easy (fill in all cups with label $$1,2$$, then divide equal water between $$1$$ and $$2$$). But $$n=3$$ is already nontrivial. Or is this an NP-hard problem?

I posted this question on math.SE, but the answer gives a linear program that only maximizes the minimum. This is insufficient: There may be two solutions with the same minimum, but one solution has much larger other numbers than the other solution.