Riemann Sketch

Riemann Sketch is a digital drawing aid for artists studying 5-point perspective (curvilinear perspective).

Traditional linear perspective works well for narrow fields of view, but fails when trying to capture a wide, immersive scene. 5-point perspective maps the world onto a hemisphere, allowing you to draw wide-angle views up to 180° that feel natural and expansive.

This tool helps you visualize this distortion. You can use it to:

• Generate accurate grids to guide your sketches.
• Verify curvilinear lines and spherical geometry.
• Visualize cubes to study how basic forms distort in 5-point perspective.

How to Use

The tool runs directly in your browser. Launch Riemann Sketch

Features

• Interactive Camera: Rotate and zoom to explore the spherical field of view (up to 180°).
• Dynamic Grids: Toggle and adjust perspective lines to help construct your drawing.
• Cube Study: Place and rotate 3D cubes to understand form and distortion.
• Export: Save your views to verify your work or use as an underlay for digital painting.

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For Developers

If you want to run this project locally:

1. Clone the repo.
2. Run npm install.
3. Run npm run dev to start the local server.