What is the current consensus on using Chaos Fracture with Nanite? I want to hear about other developers’ experiences in this.
Using 5.4.4, when I fracture a nanite mesh, the materials revert to world default, and the material options in the fracture editor has no effect in restoring or reassigning them.
Also, I cannot select pieces of the fractured nanite geometry like I can with non-nanite geometry. I can only select the whole mesh, so adding additional fracturing to pieces is not possible.
I’m only just starting to get used to the chaos fracture tools, so perhaps there is a step in the process that I’m not aware of.
What are some of the issues other people have had using fracture with nanite?
Material should be working fine with nanite geometry collections
Have you check that your material has the “use with nanite” option checked?
If so, is your material transparent?
As far as I remember the geometry collection renderer only support opaque or masked materials when nanite is on
Regarding the selection, this is a known issue
The selection works, ( you can see it changing in the bone hierarchy in the fracture editor ) but the selection overlay does not work with nanite rendering
you could disable nanite temporarily on the geometry collection asset as a work around
( there’s a check box in the asset properties for that )
I did some fiddling around and managed to accomplish piece selection from the fracture editor list. This solves one of the issues that I encountered.
I also managed to get the assigned materials to show up. The viewport just wasn’t reflecting the changes until the object was clicked on again (I guess clicking an object refreshes or reaquires its attributes?)
The remaining issue (and most pressing one) is that the interior materials wont assign to the interior faces. I’ve tried to set the index at the moment of fracture, and in the fracture material editor, but it doesn’t seem to have any effect.
The viewport just wasn’t reflecting the changes until the object was clicked on again (I guess clicking an object refreshes or reaquires its attributes?)
I’d expect the change to be applied immediately when pressing the tool Apply button
But maybe there’s a bug, I’ll have to test on my end
Are you using a geometry collection actor or is your geometry collection is in a blueprint ?
I’ve tried to set the index at the moment of fracture, and in the fracture material editor, but it doesn’t seem to have any effect.
I had no issue in recent dev builds with this
But I haven’t tried in 5.4.4. I don’t recall any change done in this area since 5.4 , so I’d expect to behave the same
Does that happen when disabling Nanite ?
For myself, in 5.4.4, I have been using geometry collections in the level. They aren’t a part of any blueprint.
When I turn Nanite off, everything runs perfectly- viewport updates real time, interior materials get assigned. I don’t have any problem with non-nanite meshes.
Fwisw, i scripted my own GC (no not garbage collector) a few years back, since, i have never even bothered looking at the engine stuff.
Chaos is trash. Nanite much the same.
A custom built engine on PhysX will solve most of the real issues you get during development.
And also, it’s nicer to he able to have stuff you want happening with the geometry collections, like runtime based mesh fracturing via procedural slicing for instance, or just a pre-pachaged and highly manicured fracturing setup.
I don’t think the engine built in stuff offers any of that type of modularity. At least, it didn’t when I decided to make my own module…
@SpareHexGames, I found and fixed a bug in the dev branch that that could effectively set all the materials to default on a Nanite geometry collection if one of them was not compatible with nanite (This will be included in the next release)
I’m not sure if that would fix the issue related to interior assignment though
Do you have a video of the issue? that could help me better identify if there’s any step taken that could be missed / lead to the issue
Regarding the selection, I put also a fix that will show what pieces are selected in the 3D viewport when using Nanite ( this will also be included in the next release )
I’m glad to hear that you found a bug! Hopefully it will help with the material assignments.
This account is a new user, so I don’t think that I can attach the video. It is a thirty second clip of me rotating the fractured mesh, and turning the nanite option on and off in the geometry collection asset. You can tell clearly when I switch it on/off because the interior faces lose their material, and the object rotations no longer update in real time in the viewport.