zalo/full-spectrum

Full Spectrum is a browser-based tool that simulates what a 3D-printed object would look like if you printed it in full color using a limited set of translucent filament colors. Instead of needing a specialized multi-material 3D printer to test color results, you upload a 3D model file and the simulator shows you how layering those filaments would reproduce the model's textures and colors. The project tackles a specific challenge: reproducing a wide range of colors from only six filament options (cyan, magenta, yellow, orange, violet, and black, plus a white base). It does this by treating each filament as a translucent filter that absorbs certain light wavelengths. The software calculates, for every point on the model's surface, which combination of filament layers to stack so the resulting color best matches the original. It uses a perceptual color-matching approach, meaning it prioritizes colors the way human eyes actually perceive differences. What makes this project notable is how it handles gradients and smooth color transitions while respecting how 3D printers actually work. Rather than just flattening colors into patches, it propagates color error upward along the print direction, simulating how a real printer would compensate layer by layer. It also ensures that neighboring areas with similar colors get the same filament sequence, so the print head isn't constantly switching materials mid-row. The primary users would be anyone working on multi-color FDM 3D printing, whether researchers developing printing algorithms, hardware makers designing filament systems, or hobbyists curious about what's theoretically possible with a limited filament palette. The simulator includes a few sample 3D models and lets you drag in your own, with sliders to adjust parameters like the maximum number of filament layers per spot or the number of height bands the model uses for error diffusion. You can export the processed result as a PNG image. The entire project runs as a static website with no build step, and the filament color values are kept in a single file so they can be swapped out for real measured values if you have them.