Why is my normal maps 3D model too heavy?

Your 3D model with normal maps is too heavy usually because of high normal map resolution, excessive base model polygons, or unoptimized texture formats. High-res normal maps (like 4K+) add significant file size. Too many polygons make the model itself bulky even with texture details. Uncompressed formats (e.g., BMP) bloat size more than compressed options (e.g., PNG). Try downscaling normal maps to 2K (if visual quality holds) or using a model optimization tool to reduce polygon count—this often cuts weight without losing key details.