🧊 OpenGL Marching Cubes

A Computer Graphics project.

This project focuses on 3D surface extraction using the Marching Cubes algorithm and Phong shading in OpenGL.
The result is a fully interactive Python application for visualizing scalar fields in 3D.

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Key Features

• 🔺 Marching Cubes implementation from scratch to extract isosurfaces from arbitrary scalar fields.
• 💡 Lighting & Shading: Realistic rendering using a Phong-like shader with ambient, diffuse, and specular components.
• 🌀 3D Camera Controls: Spherical coordinate camera system with mouse-based orbiting and zoom.
• 📦 Mesh Export: Export generated triangle mesh to .ply format for use in 3D tools.
• 📐 Normal Calculation: Proper surface normals calculated and normalized per triangle for lighting accuracy.
• 🔳 Bounding Box & Axes: 3D scene includes bounding volume and coordinate axes for orientation.

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📁 Structure

• src/ – Main source files including OpenGL initialization, rendering logic, marching cubes core, and shaders.
• requirements.txt – Python dependencies.
• output/ – Output .ply files (not versioned, but generated here).
• screenshots/ – Visual results of rendering (see below).

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Running the App

Requirements

• Python 3.13.1
• pip 25.0.1 or newer
• Required packages listed in requirements.txt

🔧 Setup & Run

pip install -r requirements.txt
cd src
python main.py

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Controls

• Mouse Drag: Orbit camera around origin
• Scroll or Arrow Keys: Zoom in/out
• Code Edit: Change the scalar field by modifying the scalar_field() function in main.py

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Notes

• No bounding box fitting is enforced – surfaces can extend outside the visual cube.
• The app has been tested for marching cube step sizes from 0.2 to 0.001 – lower values are untested but theoretically supported.
• Performance scales non-linearly with lower step sizes due to mesh resolution.

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📸 Sample Outputs

1. Surface from y - sin(x)cos(z) at isovalue 0
2. Surface from x² - y² - z² - z at isovalue -1.5