Convert 3d to x3d

What is the difference between .3d and .x3d?

Description: 3D drawing CAD Data files are computer-aided design (CAD) files that contain three-dimensional models of objects. They usually contain information on the material characteristics, lighting and coloring, and measurements of the objects. 3D drawing CAD Data files are used in 3D printing, animation, and engineering projects.; X3D (Extensible 3D) is a royalty-free open standard file format used to represent 3D computer graphics. It is used to store and interchange 3D model data, including surface geometry, color, animation, and metadata. X3D files are built on the XML standard, and can be viewed and edited with a variety of 3D modeling programs.