[css3-transforms] Some issues about backface-visibility and preserve-3d attributes

Hi all,

I posted a few concerns about the 3d transforms spect, for
backface-visibility and preserve-3d attributes, on their bugzilla page.
 Instead of repeating the information, here are the links to the issues:

I think spec is wrong about how to correctly implement backface-visibility
checks:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23014

preserve-3d semantics can be interpreted in two different ways, can we
please clarify the spec:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=23015

I hope to hear people's feedback and ultimately get the spec updated if
possible.

Best,
~Shawn