Crackle Glass or Cracked Glass

So I want to try to model Crackle glass for a personnel challenge, but really have no idea where to start. Any ideas? I thought about bump mapping but I don’t think it would look much like this…
http://i618.photobucket.com/albums/tt266/fmx230/th_005.jpg
http://i618.photobucket.com/albums/tt266/fmx230/th_004.jpg

in cycle

there is a script to make cracks for 2.6 also
see wiki page

If you wanted to get really hardcore you could use the fracture tool (in the add-ons) to make physically accurate cracks. Just make sure you don’t use smooth shading to render the result; the edges will look funky.

A more economic alternative would be to map a glossy texture to a voronoi pattern. I think I’ll go and try that right now.

I just tried the fracture tool, not exactly accurate but close.

http://i618.photobucket.com/albums/tt266/fmx230/3D%20Stuff/th_Untitled.jpg

Thanks for that tutorial Ricky, ill watch it and see if I can use anything from it.

(edit)
Without smooth shading, better but still not there
http://i618.photobucket.com/albums/tt266/fmx230/3D%20Stuff/th_Untitled2.jpg

(edit again)
Tried bump mapping in cycles, looks pretty bad.
http://i618.photobucket.com/albums/tt266/fmx230/3D%20Stuff/th_Untitled3.jpg

IDK, the top fracture image looks pretty good, and with a little tweaking could probably give yo want you needed.

Yeah this time I used two particle systems for small cracks and larger ones and duplicated the amount of vertices on the mesh.

Results are pretty good
http://i618.photobucket.com/albums/tt266/fmx230/3D%20Stuff/Untitled3-1.jpg