Intentional rough edges (and a blender love letter)

Hello!
I’m really excited you guys. It’s been YEARS of me slowly learning Blender, and admittedly, I haven’t really given it my all - until recently.

The image below represents days of work for me. I know most of you could do this in your sleep, but sheesh, cell fracturing, constraints, modeling, projection texturing, and physics…I had never done anything beyond modeling. So this was a great learning experience and I can’t wait to dig deeper! Blender opens up a world of possibilities, and as a film maker who doesn’t have a non-cg budget (or a ‘budget’ at all…) this is extremely amazing. The cycles rendering engine maybe the coolest thing since the keyframe.

But I’ve hit a wall (pun). I cannot for the life of me figure out how to make the edges on the cell fractured objects appear jagged, chipped, and more like concrete or drywall would break, and less like glass. If this is what I end up with for this project, I’m still really pleased, but I thought I’d ask you guys what you thought.

Oh, and not that it really matters for this post, but this is part of a project for an X-men short I’m making (Gambit blows up a wall). If you’d like to see it when it’s done, please check out my youtube channel (sethdeming).

Here’s what I got (notice how the parts around white wall appear super sharp):