Im doing this cake for a wedding in about a month, i have this pattern, but how do it get it on there so perfect? Im doing it on buttercream not fondant. Thanks

The diamond quilting can be done two ways (on buttercream) -- with a metal diamond quilter (Jennifer Dontz.com sells them) OR with an impression mat (Sugarshack sells them.) Make sure your buttercream is crusting or it won't work.

From Graceful Cake Creations
I was thinking it must be an artist's rendering, but then I looked at the website... might be real at that.
http://www.flickr.com/photos/gracefulcakecreations/
Here's an extreme closeup of one of their cakes with the same design.
http://farm3.static.flickr.com/2668/4048688188_a663d30656_o.jpg

I have used the diamond impression matt successfully on buttercream. Just let it crust first.