Devlog

Why breaking a block takes exactly as long as it should

On the hardness×tick break formula, the ten-stage crack, and why destruction costs time while creation stays free.

Rowan Calder — Founder / Design · 2026-07-08

Cairn is three verbs long: mine, carry, place. That's the whole game, and it means the feel of a single broken block is not a detail — it is the game. So we spent an embarrassing amount of time on it.

Here is the formula, plainly. Every block has a hardness value. By hand, break time is hardness × 1.5 seconds. While you hold your aim on a block, the game accumulates damage every simulation tick — one tick every 1/20 of a second — and when the accumulated damage crosses the block's threshold, the block breaks and its drop pops loose. That's it. No hidden multipliers, no secret luck. Aim, hold, count the ticks, done.

People sometimes ask why we tie break time to a real clock rather than to a number of clicks. The answer is that a clock is honest. A click-count can be gamed, mashed, and abused; a duration cannot. When a stone block takes its full stretch of held attention to come apart, you felt that stone. Your wrist knows it was heavier than the sand beside it. We didn't have to write "this is hard rock" anywhere — the seconds said it for us.

The ten-stage crack does the talking

A duration with no feedback is just waiting, and waiting is the enemy. So the moment your damage starts to accumulate, a crack decal blooms across the targeted face and deepens through ten discrete stages. Stage one is a hairline. Stage ten is a spiderweb about to give.

Ten was a decision, not an accident. We tried a smooth continuous crack and it read as mush — you couldn't tell how close you were. We tried four stages and it felt like a loading bar with three notches, coarse and impatient. Ten is the sweet spot: fine enough to feel like real progress, coarse enough that each new stage is a small event you can see land. Pair that with the wireframe target outline snapping to whatever's inside your 4.5-block reach, and you always know exactly what you're spending time on.

The crack isn't decoration. It's the game promising you: keep holding, this is working, you're almost there.

The asymmetry is the whole philosophy

Now the part I actually want to defend. Breaking costs time. Placing costs nothing. When you set a block down it lands instantly — no wind-up, no meter, just a clean, immediate thock and the block is there.

That asymmetry is deliberate, and it is the heart of how Cairn feels to build in. Think about what each verb means:

Destruction is subtraction. You are removing something the world had. It should carry a little friction — a small toll of attention — so it never feels careless.
Creation is addition. You are giving the world something new. It should feel weightless, generous, almost frictionless, so you never hesitate to try.

If placing had a timer too, building would feel like paperwork — every block a tiny transaction. Instead, once you've mined your material and carried it home, the act of shaping it is pure flow. You can lay a wall down as fast as your hands can move, tear out the corner you don't like (a short, honest cost), and lay it again. The cost lives in the raw material, not in the expression.

This is why a long building session in Cairn feels like the game is on your side. The world made you earn the stone. Then it got out of your way and let you be generous with it. Mining is where you pay; placing is where you're paid back.

Tuning by feel

None of these numbers came from a spreadsheet first. They came from breaking ten thousand blocks and asking, every time, did that feel like it weighed the right amount? The 1.5-second base got nudged for months. The tick rate we locked at 20 because it's fast enough that accumulation feels continuous but slow enough to stay perfectly predictable. If a block ever feels wrong to you in 0.9, tell us — that's the most useful bug report we get.

Mine slow. Place fast. Build like the material was a gift, because it was.

— Rowan