I needed a resizable hex grid pattern for a surface of a design so I made one. The pattern is customizable in size, hight and width. You can produce your own STL file online with the Thingiverse Customizer to fit your specific need.

There is a round version of the pattern here: https://www.thingiverse.com/thing:1065143

For whatever reason the Thingiverse Customizer often fails to load for me. If that happens you can download OpenSCAD from http://www.openscad.org/ and use it directly on the model. OpenSCAD is a breeze to install and use. It is also much faster than the Customizer. Another option is to switch browser. I have had better luck with Firefox than with Chrome.