How can i fracture a solid with a hole in Dataflow?

Development Programming & Scripting Blueprint
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1

I have a question about fractures in Geometry Collection.

How can you accurately fracture a solid object with holes, like a wall with windows?

I saw a tutorial somewhere before that said you should slice along the window frame to create a convex collision.

I sliced ​​the wall horizontally twice, dividing it into four parts, as shown in the image.

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However, even if i create convex collisions with slicing, there will still be collisions inside the window frame.

In the dataflow, Voronoi fracture is performed after the Planner.

I tried changing the order and running Flatten, but the collision inside the window frame did not disappear.

How can I fracture a wall while still leaving a window hole?

2

Hi

Each piece will get it’s own convex, but the cluster may generate a convex on its own covering the opening
Dataflow offers you want to generate convex from the parts

if you the starting mesh you are starting with have proper collision ( set in the mesh editor ) you have the option to import them for the geometry collection as well ( Dataflow nodes have option for that and there’s also an option in the asset itself ( called Import Collisions From Source)

Here’s an example on how you can generate convex that avoid the empty space:
in the dataflow convex nodes , there’s often an option called “Protect negative space”
this option will create sphere in the empty space and when creating the convex hulls, will make sure the hull never intersect the spheres

I hope this helps

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1 Like
3

Thank you it was helpful!

4

However, using Create Leaf Convex Hulls makes the entire collection unfracturable.

It seems to work just by enabling the Import Collision from Source option.

I don’t really understand…

5

I’m glad this was helpful

Other techniques to generate more accurate convex hulls, is to

  • Fracture your model
  • Generate the convex for the leaves
  • Generate cluster convex from the leaves
    in that case the cluster will aggregate and merge the convex from its children and you will also have the ability to control the negative space