Geometry of the perfect rebound
Every surface in Rebound obeys one law, then bends it. This is the math the game runs — kept friendly, kept honest.
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One law, stated plainly
Every launch in Rebound follows specular reflection: the angle your Orb arrives at is the angle it leaves at, mirrored across the surface normal. If you've ever watched a billiard ball, you already know the rule — the game just builds a world out of it.
The preview line shows your first two bounces. Everything after that is the game trusting you to internalise the rule. Most players stop consciously calculating by world three — the geometry moves from your head to your hands.
What each surface steals
Timber absorbs about an eighth of your momentum per contact — soft, forgiving, quiet. Steel keeps nearly everything and rings about it. Ice keeps almost all of it too, but offers zero grip for mid-flight corrections. Portals preserve momentum entirely; they only translate position and re-orient the exit.
This is why 'the same shot' never is. A line that clears a steel corridor dies against a timber wall — not because the angle changed, but because the wall took its tax.
- Timber: −12% momentum per bounce
- Steel: −2% per bounce, maximum ring
- Ice: −3% per bounce, no mid-air control input
- Portal: 0% loss, re-orients exit vector
The preview line is not the game playing for you. It's the game showing you what it already knows — the rest is trust.
Where the physics bends
Gravity rings curve your arc mid-flight — the only place straight lines stop applying. Charged glass adds a polarity impulse at contact, effectively redrawing the surface normal at the last instant. And the infamous magnet jaws don't reflect you at all; they capture and re-launch on a fixed timer.
These exceptions are the game's vocabulary. Once you can name which rule a surface is breaking, you can plan for it — and that planning is the entire skill.
Next time a chamber feels impossible, ask which surface is taxing you. It's almost never your aim.
Dana Kessler
Dana builds chambers by day and breaks them by night. She wrote the friction tables the Atlas quotes.
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The Strategy Atlas has the full friction tables and timing windows — the numbers this article summarises.
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REBOUNDAUSTRALIA