Any idea how to voronoi fracture displacement?

[ben_hamburg]

The title might be misleading, so here is what I want:

Again, playing around with tyFlow....:
I have a bunch of voronoi fractured pieces. For enhanced realism I want the capped faces from the voronoi fracture to have some noise displacement, sort of like the rayfire asperity modifier at rendertime...
I can set up a multisubmaterial, where only the capped faces material has displacement, but of course the faces get torn apart from the faces...
Since the fracturing happens procedurally, I can´t bake any textures, so I was wondering:

1. Is there currently a way to not have the edges between displaced material and non-displaced material torn apart?
2. If not...can I put that on the wishlist...? Somekind of advanced distancetex map, that either calculates the edges of two materials and creates a blend mask, or some kind of curvature/normal based map, that we could use as blend mask...

[MANUEL_MOUSIOL]

Couldn't you use UV mapping channel on the fragmented sides and set the displacement mod to that channel so that only the mapped sides get displaced, but with keep continuity on? Just an idea from the top of my head..
but yeah, having all the displacement mod options available for material displacement would be helpful in general .Just today I had the same problem and had to split geometry for it to work....

[joconnell]

You have to make a mask as you've talked about, depending on the particle system you can normally put out some kind of vertex mask for the new edges and use that to limit your displacement to specific areas. Use that with noises / procedurals / triplanars is the usual approach. It'll displace all over from the modifier but the mask will turn down the intensity. Usually there's a bit of blending between values if the mesh is low res too so it kind of gives you a bit of a softer falloff to give the displace more space to gradually roll off.

[ben_hamburg]

MANUEL_MOUSIOL : the Continuity checkbox helps somewhat, but its not good enough.

joconnell: Are you talking about a stack approach with vertex selection? I´ve tried some stuff there, but it doest work with changing topology, like in a dynamic fracturing setup, thats why i was looking for a rendertime method...

[joconnell]

Unless you're lucky enough to have a flat surface at fracture time where you can map things at frame 0 of the sim then you're kinda relying on whatever tyson is giving you feature wise to grab the new faces :/