Why PLY 3D model is huge size in file formats?

PLY 3D model files are often large because they store uncompressed geometric data (vertices, faces) and optional attributes (color, normals) without built-in compression. The format prioritizes preserving raw, detailed information—essential for 3D scanning or scientific visualization—so it doesn’t compress data or strip extra details, unlike formats like GLB or FBX that support compression. To reduce size, try removing unnecessary attributes (e.g., unused color data) or converting to a compressed format like GLB, but note this may lose some detail.