fracture Layered Fracturing (Shatter) giving the usual artifacts

[m-egger]

Before elaborating, I am not a huge fan of the material fracture solution, which also gives similar issues. Apart from the node just taking 10 seconds to place. 10,605 children in 18.0 and >11,000 in 18.5.

Also, the performance I was getting out of it was really not useable, so I'd always go back to looping over pieces and shattering (the usual) where I'd have control over the iterations and such. But maybe I'm just really too dumb to use the materialfracture correctly to get well tweaked results out of it, in a workable speed.

 

So instead I've been trying to build a more lightweight solution to use which is a voronoi fracture which brickers the cutting geo and replaces the voronoi with a shatter.

The issue is that the shatter apparently just gives bad output geometry when trying to fracture a second time, the geo is just completely broken.

 

This is the base output which is marvellous. It almost stays interactive (0.1s / frame) while the materialfracture SOP would take around 10 seconds to calculate for a similar result.

 

This is a preview of the cutting planes generated from the voronoi source points.

 

When looping over the pieces from the first iteration, the outcome is always broken like following. I've tried quite some variations of loops, but apparently the first fracture just screws up the geometry.

 

 

Any sort of cleaning/fusing would also give no better result.

Is there any way the fix the boolean shatter itself? Or to get behind why it's outputting the fracture geo in the first place?

The simple file with the asset included is attached. voronoifracture_plus_185_v01.hipnc

Thanks in advance,
Martin

Edited November 17, 2020 by m-egger

[m-egger]

Alright, I found a quite well-working solution for multiple fracture levels for the entire thing:

This is abusing the "preview cutting planes" function I built in to merge them with a second variation and then cut them in one go later.

This at least reduces the amount of times when it breaks. And it's literally 100 times faster than the material fracture. Its almost interactive at similar resolutions.

[Skybar]

If you're doing subsequent booleans you should turn off Detriangulate, it can mess things up after the first boolean. Also be vary of cutting planes that only intersect a piece of geometry half way. If it doesn't go all the way through it will cause some big problems with additional booleans.

[m-egger]

Hey David, thanks for the suggestion. I was aware of that and turned off detriangulation and made sure the faces were always extended beyond the bounding box, but the result stayed as unpredictable. 

For now, it has worked really really well to do it all in one go. I even went so far as to integrate my iterative voronoi fracture into the same cutting plane generation (before noising), so I simply got the subfractures in the first run. Really happy with the results now - the only thing I will now use the Material Fracture for when working on concrete is the chipping, but that just works appended to the boolean fracture, interestingly. I have yet to re-build the chipping myself - learning from this super intricate asset is a bit difficult.