Geyser particles

A potent sulfur geyser’s eruption is drawn by three particle effects: a column of spray (minecraft:geyser_plume), a churn at its foot (minecraft:geyser_base) and short bursts of cloud (minecraft:geyser_poof). No block, entity or animation file of the vanilla pack names them, so the engine starts them itself. Observed · every JSON file of the bedrock-samples v1.26.60.5 resource pack searched for the names How tall the eruption is and how long it lasts reach the effects as two variables that no file assigns, variable.plume_height and variable.active_time. Observed · the three geyser effects of bedrock-samples v1.26.60.5 The eruption’s sounds are individual event sounds of their own, a start and an active sound for an eruption (geyser_eruption_start, geyser_eruption_active) and another pair for a continuous one (geyser_continuous_eruption_start, geyser_continuous_eruption_active); the particle effects have no such pair. Observed · sounds.json of bedrock-samples v1.26.60.5

The effects

All three draw with the particles_blend material, a 16 by 128 texture of eight 16-pixel flipbook frames stretched over each particle’s life, and are lit (particle_appearance_lighting). Observed · the three geyser effects of bedrock-samples v1.26.60.5

Effect	Emits	Particle size	Reads
minecraft:geyser_plume	7 × plume_height particles a second, at most 5 × plume_height alive, upward from a thin box, for active_time seconds; in the emitter’s local space	0.12 × (2 + plume_height / 8 + age / lifetime)	plume_height, active_time
minecraft:geyser_base	31 particles a second, at most 45 alive, outward and upward from a half-block box, for active_time seconds	0.125 × (3 + 0.025 × plume_height)	plume_height, active_time
minecraft:geyser_poof	20 particles at once, emitter alive 0.5 seconds	0.125 × (3 + 0.025 × plume_height)	plume_height

Observed · the three geyser effects of bedrock-samples v1.26.60.5

A plume particle starts at 3 × √plume_height + 1.04 × plume_height blocks a second, with a drag of 1.2, a fall of 8 blocks a second² easing to 2 by the end of its life and a sideways spread that grows with its age, and lives ln(1 + 0.15 × (3.74 × √plume_height + 1.04 × plume_height)) / 1.2 seconds. Observed · geyser_plume of bedrock-samples v1.26.60.5 The constants are tuned so the spray tops out near plume_height blocks above the vent. Inferred

What the variables hold

Java Edition sizes the same three particles by the depth of water over the potent sulfur block: its plume height is 5 blocks per block of water (at least 5), a plume particle grows from 2 + plume height / 8 to 3 + plume height / 8 units of its base size, and a base or poof particle is 3 + 0.125 × water blocks. Observed · Java Edition 26.3’s geyser particle classes With plume_height at 5 blocks per block of water, Bedrock’s plume size is Java’s, and its base and poof size, 3 + 0.025 × plume_height, is Java’s 3 + 0.125 × water blocks exactly; so plume_height is the same plume height, in blocks. Inferred

Java’s eruption lasts 20 ticks (1 second) and bursts 20 poof particles every 10 ticks, where Bedrock’s poof is 20 particles over a 0.5-second emitter. Observed · Java Edition 26.3’s geyser particle classes active_time is then the eruption’s length in seconds, and the poof is started again for each burst. Inferred

What does the engine set plume_height and active_time to?

Neither value is published, and nothing in the packs assigns them. The fit with Java Edition’s sizes points to 5 blocks per block of water, but the eruption’s length, how often the poof is started, and whether a continuous geyser (lava under the block) restarts the plume and base or keeps one emitter alive have not been measured in the game.