X3D Export - adding a title

Question

Is there a way to add a title to an X3D (3D) plot that is exported using Export[]? I didn't have much success with exporting a Text[] into an X3D file. I also know that X3D files have several properties (meta tags) that could be helpful, but I don't know how to specify them in the Export[] command.

plot = Plot3D[x^2 + y^2, {x, -2, 2}, {y, -2, 2}, PlotLabel -> "MyPlot"];
scaledPlot = plot /. Graphics3D[gr_, opts___] -> 
   Graphics3D[GeometricTransformation[gr, ScalingTransform[{1, 1, 0.5}]], opts];
Export["plot.x3d", Show[scaledPlot, Graphics3D[Text["MyPlot"]]]]

Answer 1

I think the answer is: No, it cannot be done using Export alone. According to the documentation, there is no meta data listed in the elements available for export, nor in the options.

To accomplish what you would like to do, however, can be done via a two step process. First, save your plot as an X3D file, and the Import it as an XML file, as follows

Export["plot.x3d"]
plotxml = Import["plot.x3d", "XML"]

Then, it is just a matter of inserting your element into the XML tree. From a brief browsing of the X3D spec, I am not sure of the specific element you need to insert you data into. Likely, though, your new element will be a MetadataString, so it should look like

mdat = XMLElement["MetadataString", {"name" -> "Title", "value" -> "MyPlot", ...}, {}]

And, once you have found which element it belongs in, you can use

plotxml = plotxml /. XMLElement["ParentElement", attrs_, data_]:>
   XMLElement["ParentElement", attrs_, Append[data, mdat];

It is likely that you will have to specify the attrs list to only affect the specific element you are looking for.