Liquid #

Liquids are special dynamic nodes in Luanti. They behave quite differently than in real life. Liquids like to spread and flow to their surrounding blocks and players can swim and drown in them.

Liquid forms #

Liquids usually come in two forms: In source form and in flowing form.

Liquid source #

Liquid sources have the shape of a full cube. A liquid source will generate flowing liquids around it from time to time, and, if the liquid is renewable, it also generates liquid sources (see below). A liquid source can sustain itself. If no special event happens, a liquid source will keep its place forever and it will never drain out.

Flowing liquid #

Flowing liquids take a “sloped” form and never the shape of a cube. Flowing liquids spread around the map until they drain. A flowing liquid can not sustain itself and always comes from a liquid source, either directly or indirectly. Without a liquid source, a flowing liquid will eventually drain out and disappear.

Liquid properties #

A liquid with a flowing range of 2, viewed from above

All liquids share the following properties:

All properties of nodes
Renewability: Renewable liquids can create new sources (see below)
Flowing range: How many flowing liquids are created at maximum per liquid source, it determines how far the liquid will “spread”. This is a number ranging from 0 to 8. If 0, no flowing liquids are generated at all. Usually, liquids have a flowing range of 8
Viscosity: How slow players move through it and how fast new flowing liquids are created (i.e. how fast the liquid spreads)
Drowning damage: If set, it will a) reduce your breath (“bubbles”) while you are inside and b) will cause this amount of damage to you every 2 seconds if you ran out of breath while inside

Behaviour #

Creation of liquid sources #

Renewable liquid sources create new liquid sources at open spaces. A new liquid source is created when:

Two renewable liquid nodes of the same type touch each other diagonally
These nodes are also on the same height
One of the two “corners” is open space which allows liquids to flow in

When those criteria are met, the open space is filled with a new liquid source of the same type:

2 liquid sources (S) touch each other diagonally, but are separated by solid nodes.

The solid block at the top “corner” has been removed and a completely new liquid source block fills the empty space shortly after.

For comparison, a non-renewable liquid just flows (F) instead.

Interaction with liquids #

Swimming and diving #

Swimming in a liquid is fairly straightforward: The usual direction keys for basic movement, the jump key for rising and the sneak key for sinking. Note that the controls are different if the pitch move mode is enabled.

The physics for swimming and diving in a liquid are, in detail:

Your movement speed in a liquid is determined by its viscosity
If you don’t do anything in a liquid, you will slowly sink
There is no fall damage for falling into a liquid
If you fall from a great height into a liquid, you will be slowed down on impact (but you don’t come instantly to a halt). Depending on your speed, you might end up deep in the liquid. The slow-down effect is much stronger for liquids with a high viscosity. For a safe high drop into a liquid, you need to make sure there is enough liquid above the ground, otherwise you might still suffer fall damage by hitting the ground.
Liquids may cause breath loss and drowning damage (see above)

Pointing to liquids #

Liquids are usually not pointable. However, all liquids can be pointed by special items. In Minetest Game, one example is the bucket.

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