Question: more info on x3d format

I'm looking for information on the x3d format, with a view to converting x3d to 3d-pdf.

1. x3d formats are available from standard gui by right-clicking to "export".  How can you use plotsetup to access the "Extensible 3D" format with a line of code?
2. what x3d viewer do you recommend?
3. do you have any tips on converting x3d to pdf?

Let me elaborate to provide context to my questions. In a previous post (http://www.mapleprimes.com/questions/123177-Exporting-3D-Plots-In-Maple-15) I explained my difficulties in getting decent-looking 3d plots with Maple. (I'm on Maple 15 standard) One suggestions there was to use third-party software to handle the data generated by the Maple plot. Unfortunately my plots are a little messy and I wasn't able to do that. (Reference here: http://www.mapleprimes.com/questions/123177-Exporting-3D-Plots-In-Maple-15#comment123286).

I then came across a software that can convert x3d to pdf. This has the additional advantage that the plot can be rotated with a mouse movement within the pdf format! I've  been successful with simple plots. Unfortunately I've had problems there too with the data exported by Maple in the case of more complicated plots. 

I've had partial success using a converter written by Michail Vidiassov, which converts from Maple's Extensible X3D to PDF. Here's the
reference:http://sourceforge.net/projects/asymptote/forums/forum/409349/topic/4503534
Unfortunately, it has problems interpreting some of the data (Maple's Extensible 3D exporter returns NaN data).

Maple's help does not return anything when x3d is queried, so I suspect this is not a well documented and not very popular (yet?) feature.

Lastly, I've tried several x3d viewers, but the results are quite inconsistent. I've tried FreeWRL, InstantReality Player, Flux Player, Swirlx3d, xj3d, and a few others I was not able to run. Can you recommend an x3d viewer to use with Maple's exported x3d format?

I can provide a specific description of the problems on demand, but will wait until I'm sure I have at least one correspondent on this.