I’ve been searching for a while how to get the number of chunks that exist from a destructible mesh. I’m working on a project in which I would need to get the debris count all the time as when they disappear I would see how many remaining pieces are here. I feel like that a simple thing but I don’t see how you’re supposed to get this info through blueprint.
Hey there @misterrider! Welcome back to the community! Your intuition is correct, you can’t easily get this information in blueprint alone, though it’s not as straightforward as you’d think! The way the hierarches for the fractures work causes some fun side-effects to work around. This may not be the cleanest or most effective way to do this, as this is my first foray into processing chaos fractures.
I spent some time working out how I could first count the pieces, then translate it to a Blueprint Library plugin so you can use it directly without much extra work.
For those that just want a plugin to do it, here you go:
ChaosCounter.zip (14.7 MB)
How to use it:
Unzip the plugin folder itself and drop it in your project’s Plugins folder. If you don’t have one, make one in the project’s primary directory.
You may need to activate it in your Plugins menu once the engine is launched depending on some settings.
After it’s been activated, you can go to your blueprint that houses the geometry collection and use the new blueprint node Get Active Piece Count. An example of how I set up testing is here:
However, if you just try to use it this way with a default fracture, you will realize it outputs only 1 before the break and the maximum afterwards. This is because there is no hierarchy in the breaks, as the array that holds the fractures information such as their active state and how many are separated is based on the hierarchy.
By default all pieces will be separated from tier 0 (the root of the hierarchy) on break, any at the bottom tier are individual pieces to be counted. So when you’re fracturing your mesh, you need to fracture tier 0, then the tiers below it individually like this example where I used 3 separate slices:
Give it a shot and let me know if this works for your use case!