Temperature & Heat Strength ¶

About This Documentation

These docs were generated with AI assistance and are continuously improved.

Hot blocks get weaker. A steel beam in a fire sags. Stone next to lava softens. Wood chars away. This page explains how strux turns a block's temperature into lost strength, and how to tune it. All keys live under the temperature-strength: section of config.yml.

This feature is off by default. When it is off, temperature never changes anything — physics is exactly as it was before.

What it does¶

Every block has a load capacity — how much weight it can hold before it breaks. When this feature is on, that capacity shrinks as the block heats up.

A block that was safely holding a roof can suddenly fail once it gets hot enough, and the roof comes down. Cool it back to normal and it is strong again (unless it already cracked — see thermal shock below).

The real curves¶

Strux does not invent the numbers. It uses the same strength-vs-temperature curves that fire engineers use, one per material family:

Family	Holds full strength to	Half strength near	Gone (≈0) by	Source
Metal (iron, gold, copper, …)	~400 °C	~570 °C	~1200 °C	Eurocode 3 (steel `k_y,θ`)
Masonry (stone, brick, concrete, glass, …)	~100 °C	~570 °C	~1100 °C	Eurocode 2 (concrete `k_c,θ`)
Wood (logs, planks, …)	~100 °C	~200 °C	~300 °C (char)	char-front model

Between the listed points the strength is interpolated in a straight line — an honest reading of measured data, not a made-up multiplier.

So at 600 °C, a steel block keeps about 47% of its strength, concrete about 45%, and wood is already gone.

How hot is hot? (the °C mapping)¶

Minecraft has no thermometer, so strux maps its blocks to plausible real temperatures:

Source	Temperature
Lava	≈ 1100 °C
Fire / soul fire	≈ 800 °C
Magma block	≈ 400 °C
Snowy / frozen biome ambient	≈ −10 °C
Temperate biome ambient	≈ 20 °C
Desert / badlands ambient	≈ 45 °C
Nether ambient	≈ 60 °C

A nearby ice or snow block pulls a block's local ambient down toward freezing.

A heat source's effect fades with distance and through solid blocks. So the outside face of a thick wall cooks while its interior stays cooler — and therefore stronger. A thick wall really does resist heat better. (Tune this with solid-insulation-blocks.)

Thermal shock (heat, then douse)¶

Heat a brittle block — stone, brick, fired ceramic — and then suddenly cool it (throw water on it, let rain hit it, or remove the lava) and it cracks. The crack is permanent damage, like a hit from an explosion.

This is the siege tactic: heat an enemy wall with fire, then douse it, and it shatters. Ductile materials (metal, wood) barely care — only brittle ones crack. The crack only fires for a cooling that happens while the block is under load — a block that heated up, calmed down, and is only stressed much later won't shock-crack from that old, forgotten heat.

shock-onset-c — a temperature drop smaller than this cracks nothing.
shock-span-c — a drop this much past the onset cracks the block as hard as it can.

Settings¶

temperature-strength:
  # Master switch. false = temperature never changes capacity (default).
  enabled: false

  # The °C of an unheated block in a temperate biome.
  comfort-temperature-c: 20.0

  # Thermal shock: the smallest sudden DROP (°C) that cracks anything.
  shock-onset-c: 150.0
  # The drop past the onset at which cracking is maxed out.
  shock-span-c: 500.0

  # How far (blocks) to look for heat sources around each tracked block.
  scan-radius: 5
  # Distance at which a source's heat halves.
  heat-falloff-radius: 4
  # Extra falloff per solid block in the way (the "thick wall" knob).
  solid-insulation-blocks: 3.0

  # How often the scan runs (ticks; 40 = 2 seconds).
  scan-interval-ticks: 40
  # Most ms one scan may spend before it yields the tick.
  tick-budget-ms: 10.0

Per-material tuning¶

Each block already has a thermal family by default (metals → steel curve, stone/brick/glass → masonry curve, logs/planks → wood curve). You change a block's other properties — mass, max load, blast, fire — through the usual materials: overrides; the thermal family is kept when you do.

A block's thermal family is now saved with the world and survives a restart. Before, a steel beam reloaded after a restart forgot it was steel and stopped weakening in heat until it was touched again; now it keeps its family across save and load. Old save files made before this fix have no family stored, so every block in them loads as "no temperature softening" (the same strength they had on the old version) until it is next placed.

What this is NOT¶

This is a material-strength model: it lowers how much a hot block can carry. It is not a full thermal-stress simulation — strux does not compute the internal stresses that uneven heating and expansion create inside a block. That is a deliberate omission to keep the physics fast and easy to follow. Thermal shock is the one nod to transient heating effects, and even it is a calibrated crack, not a heat-flow equation.

Temperature never touches moisture — that is the weather system's job — and a block that fire is already actively burning is left to the fire model alone, so heat is never counted against the same block twice.