Your bottle 3D model is grainy typically due to low-resolution textures, too few polygons, or unoptimized rendering settings (like low sample rates).
- Low-res textures: Lack detail, making the bottle’s surface look pixelated. - Insufficient polygons: Curved edges (e.g., body, neck) appear jagged. - Low render samples: Cause noise from incomplete light calculations.
To fix it, try: - Upgrading textures to 2K/4K. - Subdividing the model to add more polygons (if your software allows). - Increasing render samples (e.g., from 100 to 500 in Blender Cycles).