Dr. Sassi.

Thanks so much for this approach, I have been using the Volume Mesher, which works but yields some limitations, I'm going to explore this method as your demo looks amazing.

Best!

Hi Dr. Sassi,

Thanks so much for your help unfortunately that doesn't give me quite what I'm looking for as I miss all of the detail on the 'broken' parts of the glass. This is a hero logo resolve and I need the glass to have lots of complexity and visual interest. I can run a vertex map onto the geometry controlled with a field to swap the materials as needed if I this is a dead end or just render it twice and fix it in comp. Sure would be nice though to accomplish this in a more procedural and flexible way though. I'll continue to play with it.

Best!

Ok well, I was wrong, the above only partially works. The AO and Ramp nodes together leave too much latent opacity. Meaning that if I compare the same geometry with the same material applied without the AO setup to fix the cracks I get a full featured glass material with lots of bright reflections, etc. Compared to the version that 'works' the glass is far more transparent and has loss much of its character. I'll have to try something else. perhaps a material blender? I'll post if I ever figure a solution.

Haha ok I figured out what the issue was, the solution was much more prosaic than some hidden feature of a dusty node. I simply needed to stop and start the IPR then it would work as I imagined. Once I turned the IPR off and back on it worked fine not matter the geometries thickness. Here is a breakdown of the method I used:

When using the Voronoi Fracture to break glass:

Two glass materials, one for the the inside faces and the other for the outside faces, activate and assign the relevant selection tags to the relevant geo.

For the inside faces material add and AO node connected to a Ramp node connected to the Opacity input of the material.

The AO can be left default, on the Ramp pull the black knot to 99.9%.

You should be good to go. phew.

@Jiveon ok so I think the issue may have something to do with the overall thickness of the geometry, I applied my AO based effect shader to a 1cm thick piece of geometry and the effect worked fine, anything thicker than that and the cracks begin to appear.

Hello, I'm trying to make the effect where a transparent object starts whole and then gets broken apart. The issue I'm having is the cracks continue to appear even while the object is whole. I've tried techniques suggested from both of the tutorials below but have yet to find a working solution. Any help anyone might have would be much appreciated, thanks!

An old solution using the physical shader (utilizes AO to generate black where when the pieces are close to each other):
https://www.youtube.com/watch?v=K0C7bnXmObM&t=106s

The answer is possibly in here but the reference project/image is no longer available:
https://www.cineversity.com/forums/viewthread/4975/