glass slowly cracking but not braking...

[lukx]

I'm trying to create effect of glass slowly cracking but not breaking.
Something like when you stand on ice and the cracks starting to show and grow.
I was thinking rayfire but have no idea how to do it the way that cracks show in a way I described above.
I was also thinking After Effects and tried advanced lighting but it's not it.
Anyone did something similar and can advice?

[Dariusz Makowski (Dadal)]

Depends from the concept. But consider using animated texture to do it...

[Neilg]

I'd use a map too, doing it in 3d would just be harder and give less control. You could use rayfire/whatever to generate a mask for the glass, then take that into after effects to animate it growing out.

[lukx]

sorry stupid question but I never did such thing as animated texture.... you mean have cracked texture in ae and then animate mask to reveal cracks?

[Dariusz Makowski (Dadal)]

Pretty much yes.