Generates synthetic datasets for perpendicular-bisector construction. The agent must draw the perpendicular bisector of a given segment (the locus of points equidistant from its two endpoints) and identify which of several option labels lies on it — testing geometric construction with metric (distance) constraints.
Each sample pairs a task (first frame + prompt describing what needs to happen) with its ground truth solution (final frame showing the result + video demonstrating how to achieve it). This structure enables both model evaluation and training.
| Property | Value |
|---|---|
| Task ID | Multi-27 |
| Task | Perpendicular Bisector Construction |
| Category | Constructive Geometry |
| Resolution | 1024×1024 px |
| FPS | 16 fps |
| Duration | varies |
| Output | PNG images + MP4 video |
# 1. Clone the repository
git clone https://github.com/VBVR-DataFactory/Multi-27_perpendicular_bisector_construction_data-generator.git
cd Multi-27_perpendicular_bisector_construction_data-generator
# 2. Create and activate virtual environment
python3 -m venv venv
source venv/bin/activate # On Windows: venv\Scripts\activate
# 3. Install dependencies
pip install --upgrade pip
pip install -r requirements.txt
pip install -e .# Generate 50 samples
python examples/generate.py --num-samples 50
# Reproducible generation with seed
python examples/generate.py --num-samples 50 --seed 42
# Custom output directory
python examples/generate.py --num-samples 100 --output data/my_dataset
# Without videos (faster, images only)
python examples/generate.py --num-samples 50 --no-videos| Argument | Description |
|---|---|
--num-samples |
Number of tasks to generate (required) |
--output |
Output directory (default: data/questions) |
--seed |
Random seed for reproducibility |
--no-videos |
Skip video generation (images only) |
[Scenario] The image displays a straight line segment connecting two small circles, along with several option markers.
[Rules]
1. A perpendicular bisector is a line that passes through the exact midpoint of a segment at a 90-degree angle.
2. Only one of the given option markers lies on this perpendicular bisector.
[Task] Generate a video animating the construction of the perpendicular bisector for the given segment. Keep the construction line visible, and highlight in red the option marker that lies on that bisector. Hold the final frame.
 |
 |
 |
| Initial Frame Segment with two endpoint circles + option labels |
Animation Midpoint located, perpendicular drawn step by step |
Final Frame Bisector visible; correct option highlighted in red |
Construct the perpendicular bisector of a given segment — the line passing through the segment's midpoint at a right angle — and identify which of several option labels lies on this constructed line.
- Segment: A pair of small circles marking the segment's endpoints.
- Construction: First find the midpoint, then erect the perpendicular through it.
- Option labels: A, B, C, D candidate points scattered near (but not all on) the bisector.
- Solver: Closed-form midpoint + 90° rotation; the unique correct option lies on the bisector.
- Two-step geometric construction: Locate midpoint → rotate direction by 90° to draw the bisector.
- Equidistance characterization: The bisector is the locus of points equidistant from both endpoints — a metric, not topological, constraint.
- Quantitative discrimination: Distractor options are placed close to the bisector to penalize coarse approximation.
- Visible construction trace: Midpoint marker, perpendicular line, and option highlighting are sequentially rendered.
data/questions/Multi-27_perpendicular_bisector_construction_data-generator_task/Multi-27_perpendicular_bisector_construction_data-generator_00000000/
├── first_frame.png # Segment + option labels
├── final_frame.png # Bisector drawn + correct option marked
├── prompt.txt # Task instruction
├── ground_truth.mp4 # Animation of stepwise construction
└── question_metadata.json # Standardized VBVR task metadata
File specifications:
- Images: 1024×1024 PNG format
- Video: MP4 format, 16 fps, H.264 + yuv420p
- Metadata: VBVR canonical schema with
task_id,vbvr_task_code,media,parameters
perpendicular-bisector geometric-construction equidistance midpoint multiple-choice multi-step-reasoning
Part of the 36-Task Long-Horizon Multi-Step Reasoning Benchmark.