How to convert 3D PDF
to STL?

3D PDF is a PDF file with 3D geometry inside. Using any 3D PDF enabled viewer, rotation, zoom and part selection is available within the 3D view.

3D PDF is just like a normal PDF (Portable Document Format) file, which contains a 3D view somewhere on some page. Just like a PDF containing an embedded image, except when you put the mouse over it, you can rotate, zoom, pan and explore the scene in 3D (three dimensions). The file actually contains a 3D geometric representation of the scene, not just images from different viewpoints.

STL (STereoLithography) is a file format native to the stereolithography CAD software. This file format is supported by many other software packages; it is widely used for rapid prototyping, 3D printing and computer-aided manufacturing. STL files describe only the surface geometry of a three-dimensional object without any representation of color, texture or other common CAD model attributes. The STL format specifies both ASCII and binary representations. Binary files are more common, since they are more compact.