Does anyone know about crystal cut?

Hi all,

I'm using comsol to do surface acoustic wave simulation. And all the material I read mentioned about crystal cut, like xy-cut, yz-cut, 30° rotated yx-cut. And in COMSOL piezoelectric application mode I have to specify the material orientation, like xy, yx, zx, xz, etc. I'd like to ask if there is relation between this two, which means the material cut determines the material orientation in comsol.

And even if not, I still want to know what exactly is crystal cut(I mean how to cut it, I can't imagine) and what exactly is material orientation. I searched many materials on internet but didnt find an easy-to-understand one.

Thanks in advance.

CC