README.md

---
language:
- en
- ru
license: apache-2.0
task_categories:
- text-generation
tags:
- physics
- simulation
- 2d-physics
- rigid-body
- pymunk
- synthetic
- scene-generation
size_categories:
- 1M<n<10M
---

# Physics Generalization Dataset

**1,000,020 diverse 2D rigid body physics simulation scenes** for training and evaluating LLMs on physics prediction tasks.

## Overview

This dataset contains procedurally generated physics simulations across **30 distinct scenario types** organized in 6 categories. Unlike typical physics datasets that only feature random objects falling in a box, this dataset covers a wide range of physical phenomena: collisions, stacking, ramps, pendulums, constraints, and mini-game-inspired physics.

Each scene is a 200-frame simulation at 1/60s timestep using the Pymunk (Chipmunk2D) physics engine, exported in JSONL format with rich metadata.

## Dataset Structure

### Splits

| Split | Scenes | Scenario Types | Purpose |
|-------|--------|----------------|---------|
| **train** | 900,000 | 24 (seen only) | Training |
| **val** | 100,020 | 30 (seen + unseen) | Evaluation |

### Unseen Scenarios (held out from training)

6 scenario types appear **only in val**, enabling out-of-distribution generalization evaluation:

| Difficulty | Scenario | Description |
|-----------|----------|-------------|
| Simple | `pong` | Ball bouncing between two paddles (zero gravity) |
| Simple | `bowling` | Heavy ball rolling toward arranged pins |
| Simple | `ramp_roll` | Objects rolling down an inclined plane |
| Complex | `angry_birds` | Projectile launched at multi-layer block structure |
| Complex | `hourglass` | Objects falling through narrow gap between chambers |
| Complex | `newtons_cradle` | Balls suspended by pin joints, momentum transfer |

### Seen Scenarios (in both train and val)

24 scenario types with 37,500 samples each in train:

**Collision & Ballistics:** `billiards`, `breakout`, `explosion`, `head_on`, `projectile`

**Stacking & Structural:** `bridge`, `dominos`, `jenga`, `pyramid`, `tower`

**Ramps & Terrain:** `funnel`, `marble_run`, `plinko`, `ski_jump` (+ unseen `ramp_roll`)

**Pendulums & Constraints:** `chain`, `pendulum`, `seesaw`, `wrecking_ball` (+ unseen `newtons_cradle`)

**Mini-game Physics:** `basketball`, `pinball` (+ unseen `angry_birds`, `bowling`, `pong`)

**Complex & Chaotic:** `avalanche`, `conveyor`, `orbit`, `wind` (+ unseen `hourglass`)

## Data Format

Each scene is a JSONL file (1 header line + 200 frame lines).

### Header (line 1)
```json
{
  "type": "scene_header",
  "seed": 1315353,
  "scenario_type": "explosion",
  "scenario_category": "collision",
  "difficulty": 4,
  "description": "Explosion: 25 objects flying outward from center.",
  "object_count": 25,
  "gravity": {"x": 0.0, "y": -981.0},
  "timestep": 0.016666666666666666,
  "static_geometry": [...],
  "constraints": [...],
  "objects": [
    {
      "id": 0, "type": "circle",
      "position": {"x": 401.23, "y": 302.45},
      "material": {"mass": 2.5, "friction": 0.6, "elasticity": 0.7},
      "radius": 15.3
    }
  ]
}
```

### Frame (lines 2-201)
```json
{
  "frame": 1,
  "description": "Frame 1: All objects are in motion.",
  "objects": [
    {
      "id": 0, "type": "circle",
      "position": {"x": 415.67, "y": 318.90},
      "velocity": {"x": 280.5, "y": 320.1},
      "angle": 0.052,
      "angular_velocity": 0.003,
      "material": {"mass": 2.5, "friction": 0.6, "elasticity": 0.7}
    }
  ]
}
```

## Key Features

- **30 scenario types** with qualitatively different physics (not just parameter variation)
- **Difficulty scaling** (1-5) per scenario: controls object count, velocity, structural complexity
- **Deterministic** generation via seed-based RNG
- **Constraints/Joints**: PinJoint, PivotJoint for pendulums, seesaws, chains, Newton's cradle
- **Custom static geometry**: ramps, funnels, peg grids, bumpers, hourglass chambers, basketball hoops
- **Rich text descriptions** for each scene (useful as LLM context)
- **Zero gravity** scenarios: billiards, pong, orbit
- **Initial velocities**: projectiles, explosions, head-on collisions (not just "objects at rest")
- **Clean train/unseen split** for generalization evaluation

## Physics Engine

- **Pymunk** (Python wrapper for Chipmunk2D)
- Scene: 800×600 pixels
- Fixed timestep: 1/60s
- Elasticity always < 1.0 (energy conservation, no Pymunk instability)
- Threading disabled (determinism)

## Generation

Generated using 22 CPU cores in ~29 minutes at ~578 scenes/sec.

```bash
python scripts/generate_scenarios_dataset.py --split all --workers 22
```

## File Organization

```
data_scenarios/
├── manifest.json          # Split config, seen/unseen lists
├── train/
│   ├── avalanche/         # 37,500 scenes
│   ├── basketball/
│   ├── ...                # 24 scenario type directories
│   └── wrecking_ball/
└── val/
    ├── angry_birds/       # 3,334 scenes (UNSEEN)
    ├── avalanche/
    ├── bowling/           # 3,334 scenes (UNSEEN)
    ├── ...                # 30 scenario type directories
    └── wind/
```

## Citation

Part of a research project on training LLMs to predict 2D rigid body physics.