To make a clean 3D model from a 2D image, start with a high-quality source and refine the mesh after conversion.
First, clean the 2D image—remove noise, adjust contrast, or crop distractions—to prevent messy artifacts from transferring to the 3D output. Then, in tools like Blender or Meshmixer, use mesh smoothing for jagged edges and decimation to cut unnecessary polygons without losing key details.
For beginners, Blender’s free "Smooth" or "Remesh" functions are simple and effective for fixing common model imperfections quickly.