Peripheral voronoi pieces for advanced fracturing

[Cosimo Orban]

Hi all!

I'm trying to make a Voronoi fracture based on points that are to be scattered on the volume running along the border, in a gradient fashion towards the center of the geometry. The idea is to use the points for a 2nd layer of Voronoi fracturing after the main pieces are defined.

I know there is the density attribute to drive the scattering, and you can use a volume wrangle to define the density attribute, but how do I tie the attribute to each voxel's distance to the center?

Ideally, it would be the distance of each voxel to a smaller copy of the geo, so that the density gradient is uniform and not stretched to reach the center from far-off parts.

Is there a way to do this?

Thanks!

 

[Atom]

You can use a second ISOOffset and shrink it down a bit. Feed that into a group node and activate bound by volume. Then you can delete that center area group and your scatter points will only remain along the edge. It is not so much a gradient result but maybe you can leverage density attribute on the scatter by painting along the edge.

In this image I have copied boxes to the resulting points so you can better view the hollow missing area.

ap_scatter_not_center_082518.hiplc

Edited August 25, 2018 by Atom

[Cosimo Orban]

Thanks for the reply Atom!

 

Yes, I've experimented with that (although in my case I just used a transform and group by object) but the pieces inside where still too small and in my mind the core would be a single piece in the end.

 

What I found to be quite effective is the Voronoi Fracture Points SOP, which scatters further points based on the initial scatter but, more importantly, it allows you to define the clustering and point density based on three layers of depth: surface, exterior and interior. This is very close to what I had in mind at the beginning, as the sim will now hold tight on the clusters and make the little pieces shoot out if the impact is greater than a threshold.