Using powder coating for color filling provides superior contrast and durability compared to other methods. Firstly, add outlines around the images in the design file. Carve without outlines in the first pass, fill the plastic powder into the carved patterns, and scrape it flat with a scraper. In the second pass, using the outlines to create clear black borders around the color filling. Use a damp cloth to clean the powder coating; the colored patterns created by carving will produce an orange peel-like texture.