Hi all,
The new version of Three Macro is now available.
This improves the way files are specified. Now you can use the ref parameter for specifying a single URL or a list of URLs and attachmentRef parameter to specify a single attachment or a list of attachments from any page.
More details on the extension page.
Link to the extension: https://extensions.xwiki.org/xwiki/bin/view/Extension/ThreeMacro/
Peace. 
Cool! 
Note that if you wish to be consistent with other macros, we use reference elsewhere (We don’t use shorthand notations for clarity whether in code or macro parameters).
YES. I had an idea that reference was a commonly used parameter in XWiki. Might have been better if I went through the community once.
But my reason behind ref was to support both URLs and attachments in macro-three specific parameters. I didn’t know how to name the parameter that would take in URLs so I went with ref for that leaving out the possibility of using reference for attachments (because of similar/same meaning).
May be it’s a good idea to use reference for attachments within XWiki and urlReference for the URLs. Yup, I think that makes more sense. May be I will change it with the next release when I add support for a couple of new 3D object formats
Thanks for the remarks though. :).