Hey folks.

I'd like to ask you for advice and guidance regarding localized fracturing in the new RBD tools workflow for Houdini versions 18 and above. This area has not typically been one that I've spent a lot of time in within Houdini. While I'm familiar with the RBD workflow and such, I'm not getting the desired outcomes I'm looking for just yet. I've tried the following techniques to get localized fracturing accomplished but they haven't worked well for me. Any advice from more seasoned pros out there would be very welcome. Thank you kindly.

• Isolate section of model with a boolean first then feed that into the RBD Material Fracture. Essentially works but I'm then stuck with a gross seam between the boolean parts, even if I use an assemble node afterwards to help cusp edges.
  
  
• Utilize the RBD paint node to paint density attribute and then feed that into RBD Material Fracture using the attribute method. This doesn't function the way I assumed. The entire model still gets fractured when I only want fracturing to occur where I painted density. I'm not sure what I'm missing here. The process seemed intuitive enough until it wasn't.
  
  
• Custom cutters from shape geos option in RBD Material Fracture. Cuts where I want primary shapes but then I no longer have options for multiple levels of fractures on those pieces in RBD Material Fracture. I have to assume I'm missing something obvious here or the process isn't all that intuitive. My guess is that another RBD Material Fracture node can come afterwards and perhaps be fed the pieces from the prior custom cuts. I think I fiddled with that but couldn't get it to work.
  

So there you have it. I'm hopeful that some of you out there read this and can scream at me about everything I'm doing wrong lol. I welcome any advice that helps me get the solution I'm after. Localized fractures with multilevel fracturing capability on complex models in order to optimize the fracturing process and file cache.

Thank you again for your time folks!

The concrete fracturing method is doing a voronoi fracture at its core, so the placement of the cell points determines the pieces that are produced. In particular, if you want a section of the model to not be fractured, then that section needs to be in a single voronoi cell. The attached example demonstrates that, and is probably why the scattering by density didn't quite achieve what you were after.

Doing a prior boolean fracture is also a very reasonable approach. You can append an RBD Material Fracture and use the Group field to fracture certain parts of the geometry, and turning on Fracture per Piece would make it behave more like a recursive fracture.

cwhite
The concrete fracturing method is doing a voronoi fracture at its core, so the placement of the cell points determines the pieces that are produced. In particular, if you want a section of the model to not be fractured, then that section needs to be in a single voronoi cell. The attached example demonstrates that, and is probably why the scattering by density didn't quite achieve what you were after.

Doing a prior boolean fracture is also a very reasonable approach. You can append an RBD Material Fracture and use the Group field to fracture certain parts of the geometry, and turning on Fracture per Piece would make it behave more like a recursive fracture.

Awesome. Thank you very much. This helps somewhat.