Managing fractured Primitive Groups with Packed primitives

[Jomackabee]

Hi All

 

Im quite new to Houdini and have a possibly basic problem to tackle!

 

I've set up a fracture system for a barrel I want to simulate exploding. In order to fracture each wooden plank of the barrel separatley (and avoid the voronoi fracture smooshing all the geometry together) I've used an assemble sop to split them out into primitive groups and a foreach node to iterate through each piece with my voronoi fracture setup. This seems to work well and the foreach node spits out my barrel with 25 primitive groups, each one fractured the way I want however when I create an RBD setup the second assemble SOP that creates the packed primitives doesnt pack all the individual shattered pieces correctly (either grouping to few primitives or if i tick "create name attribute" separating out every single polygon).

 

As I say im relatively new to the wonders of houdini and might be missing something glaringly obvious with the way im handling primitive grouping down the node structure but any fresh insight into how I can send my shards to DOPs correctly would me massively appreciated.

 

Thanks in advance for any help!

 

J.

FractureSetupTEST.hip

Models.rar

[cwhite]

The Pack SOP (which the Assemble SOP uses internally) creates a packed primitive for each *unique* value of the 'name' primitive attribute (i.e. for each fractured piece). I think the issue in your scene is that the Voronoi Fracture in the ForEach SOP generates names like 'piece0', 'piece1', etc each time it is run, and so you end up having multiple fractured pieces with the same name. I'd suggest changing the "Name Prefix" parameter on that Voronoi Fracture to something like

`stamps("..", "FORVALUE", "")`_

This will grab the current group name and produce unique names like plank0_0, plank0_1, ..., plank1_0, plank1_1, etc. You can also use the Exploded View node to visualize the results of a fracture.

[Jomackabee]

Thanks for the help! I most definately wouldnt have spotted that being the problem.