SimLab Soft has two products relevant to SketchUp users: SimLab 3D PDF Exporter for SketchUp and SimLab Composer (which also includes this feature). SimLab 3D PDF Exporter does what it says: exports a PDF file viewable in 3D - which you can also insert into a html page. SimLab Composer - beside being distributed in three, different "flavours": 3D PDF edition, Rendering edition and Animation edition (see the comparison here) - gives users different options to share 3D Scenes;
3D PDF: 3D scenes created in SimLab Composer, can be exported as 3D PDF files. A 3D PDF file is a PDF file (that can be opened using a free version of Acrobat reader), which includes 3D Data. The recipient of the file will be able to view, rotate, and interact with the 3D scene. 3D PDF was designed to be very easy to use for none technical users.
3D HTML (WebGL): SimLab Composer supports sharing models as HTML files that can be opened using any of the leading web browsers including Google Chrome, Fire Fox, Internet explorer and Safari by utilizing the web browser's native WebGL capabilties.
Exporting to iPad: 3D scenes created in SimLab Composer, can be exported to iPad as SimLab archive files (*.zim). SimLab Archive files can be opened using SimLab CAD Viewer.