Model Modifier works on your own files: drop in any STL, click the surfaces you want to change, and apply relief textures, full-color Pro Materials, solid recolors, or a raised name. Everything runs in your browser — the model never uploads anywhere. Surface detection splits the model into clickable regions; if it grabs too much or too little, adjust the detection sensitivity before assigning anything. Relief Depth controls how far textures displace the surface — around 1mm suits most models — and Texture Scale sets the pattern density. Download a multi-color 3MF for AMS-style printers, or a displaced STL that bakes the texture into the mesh for any printer. Texture faces that print as walls or top surfaces; downward-facing ones will need supports.