Rigid Bodies &
Static Bodies

The two most fundamental physics object types.

What you're seeing

Blue label → Static Body. The floor. Never moves. Infinite mass. Zero cost to the physics engine.

Orange label → Rigid Body. The box. Fully simulated — gravity pulls it, it bounces on impact.

The labels follow the 3D objects by projecting their world position to screen coordinates every frame. No library — just math.

Tune the physics

Mass (kg) 1 kg

🧠 Galileo fact: heavy and light objects fall at the exact same speed. Gravity accelerates all masses equally. Mass only matters when you push or throw things.

Bounciness (restitution) 50%

🎾 Tennis ball

How much energy survives the impact. 0% = all absorbed (clay, beanbag). 100% = all returned (physically impossible but fun in games).

Gravity Scale 1.00×

🌍 Earth gravity (9.81 m/s²)

Multiplier for this one box only. Each body can have its own gravity scale — great for floating enemies or zero-gravity areas.

Recreates the box at the top with your new values

Key Takeaways

💡 Physics engines don't move objects

They control VELOCITY. Every frame: position += velocity × deltaTime. Forces, gravity, bounces — all just change velocity. The engine never says "go here" — it says "now you're moving at this speed."

🏗️ Static vs Dynamic — the big split

Nearly every game is a mix of these two. Static = the environment (ground, walls, buildings). Dynamic = things that move (player, enemies, crates). Static costs almost nothing. Dynamic costs simulation time every frame.

🔑 Fixed = INFINITE mass

Not just "heavy" — truly immovable. No matter how many dynamic objects pile on, a fixed body never moves. That's how games keep floors from collapsing under a crowd.

Rigid Bodies &Static Bodies

What you're seeing

Tune the physics

Key Takeaways

Rigid Bodies &
Static Bodies