Open U3D file

The u3d file extension is probably best know for its use for Universal 3D file format.

This Standard defines the syntax and semantics of the Universal 3D file format, an extensible format for downstream 3D CAD repurposing and visualization, useful for many mainstream business applications.

Salient features of the U3D file format described in this document include: execution architecture that facilitates optimal run-time modification of geometry, continuous-level-of-detail, domain-specific compression, progressive data streaming and playback, free-form surfaces, key-frame and bones-based animation, and extensibility of U3D format and run-time.

U3D has a long, tainted and little known history. In the 1990s Intel Corp. produced a gaming toolkit referred to as "IFX". In 2000 and 2001 they tried to ply it on Macromedia as the failed Shockwave-3D file format and SDK, which basically went obsolete in early 2001 (mainly due to the dotcom bubble implosion). Adobe wanted to compete with Autodesk in the MCAD market (which ended up in failure by 2008) so in 2004 they were to adopt X3D as the standard 3D file format for the "new" 3D PDF file format, but Intel forced them to use the old IFX/Shockwave-3D file format instead -- renamed from SW3D to U3D. IFX was never designed for the conversion and viewing of CAD data (as Adobe wished to use it for in 3D PDF), so U3D eventually became unsupported and dropped by Intel after 2007, followed by Adobe selling off their 3D software divisions in Dec 2008 due to 6 quarters of poor company sales. U3D and "PRC" continue to be the internal 3D file formats used within 3D PDF files. TechSoft and their Tetra4D company was spun off years later to pick up the pieces of Acrobat-3D from Adobe and continue its long term maintenance (as well as continuing to resell the old TTF Group CAD importer modules, which Adobe had purchased for their 3D MCAD work in April 2006). U3D was best used as a light weight WEB streaming file format (such as used for the Shockwave-3D file format in the early 2000s) but it does not do well for compression of CAD data.