Been trying to do HueForge-style multicolor prints on the U1 and hit the same wall everyone does — HueForge exports STLs with height-based color changes, but the U1 is a toolchanger. It doesn’t do filament swaps by layer height, it does per-tool color assignment. The file formats just don’t talk to each other.
Built a browser tool to bridge the gap. Spectrum Forge takes any image, maps it to your filament colors, and exports a watertight 3MF with per-pixel paint_color encoding that Orca Slicer actually understands.
It also allows adjusting the aspect ratio in the page.
Two modes:
- Toolchanger Painted — assigns tool slots per color region. Built for the U1.
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- Traditional Height — classic layer-swap for single-extruder setups.
- No install. Runs in the browser. Pick your filaments, drop an image, export 3MF, open in Orca.
First 100 downloads free: inkwell.wiki/tools/spectrum-forge
Works with any toolchanger running Orca Slicer (Prusa XL, E3D, etc.) but I built it specifically because the U1 had no working path to multicolor prints from images.
Happy to answer questions about the 3MF structure or print settings. Also built a companion tool called Flat Forge for face-down postcard prints if anyone’s into that.