Can I make destructible meshes without "insides"?

Hi, I want to know if there’s an easy way to make destructible meshes which don’t create “insides”. For example, if you take the default cube in UE4 and destroy it, it’s as if it was a solid cube filled all the way through. Is there a way to make it so only the actual geometry is displayed on the destructible mesh? Imagine I have a crate which is empty, I want just the crates’ sides to break without anything extra being produced from within.

For example, I’ve made this pot


If I break it, untextured geometry is added where it broke, as if it was completely solid. Pots aren’t solid all the way through, so is the only way to display that to actually have it be an open topped pot with thickness?
This can somewhat easily be achieved with the Solidify modifier in Blender, but then that causes weird clipping sometimes and makes the creation process take much longer. And again, I have no idea how I would do that with an object meant to be closed, like this pot with a lid or a sealed barrel/box.

Any help is appreciated, thanks.

You can use the “boolean” modifier in Blender, duplicate your pot object and re-size the duplicate to be slightly smaller than the original and use the boolean mod to “cut” out of the main shape. This will create inner geometry and hollow out your pot. Otherwise when you created that object in blender it actually is “solid” all the way through. all the vertices connect, so when you use the destructible mod in UE4 it re-allocates where those vertices connect but it assumes the entire thing is solid so it can create connections where you wouldn’t want them in a “hollow” object. As ThompsonN13 said, you have to create the hollow geometry in Blender first then the destructible mod will work.

if in blender then i would actually use the solidify modifier for more complex shapes. the bool would be good is you wanted just a basic hollow. the solidify will recreate the shape with greater accuracy which of course that means more geometry as well which could be a negative. but it creates the shape and positions it correctly, so you can always go back and decimate as needed later.

the below picture chows the decimate modifier and the settings i used to accomplish the effect your looking to do. the second picture shows the result where i took the suzanne head and gave it thickness, then i made it destructable and let it fall to the ground.


Okay, thanks for the comments. For some reason they all went to my spam folder… I did actually go back and make changes to my pots that I made, I used the Solidify modifier in Blender and it works fine.

I hadn’t thought about setting solidify to negative, though. That gives it an internal face… that’s better than having the offset positive because then it’s completely accurate on the outside. Thanks for that.

An additional question would be: how do I make the gray mesh where the object breaks use the object’s texture? Pretty nit-picky for such a convenient destructible creation system, but seeing that gray mesh on a very detailed object is kinda gross.

to accomplish what your looking to do would require you to create geometry for the void. the way that basic geometry works is that the polygons dont actually have any thickness. what this means is that if viewed from the inside you wouldnt see you pot at all, as a better example plave a plane in your level and look at its backside you will be able to see right through. so to solve your issue you will need to create geometry that tells the engine the boundary of the solid area and where there should be a hollow cavity.

by the gray area im assuming that you mean the places where the mesh is broken when making it destructible and in that case your destructible mesh should have a second material slot which is what you need to change. the material options are in the skeletal mesh section in the destructible settings tab. the material should be set to world grid by default.

You are correct, I’m talking about the parts revealed by the destruction of the mush. However, I’ve only got one slot, which is the texture I made (since I applied that to the static mesh before making the destructible.) Making any additional material slots doesn’t seem to fix it.

your in the destructible mesh right? when you create the destructible and then fracture the mesh it will create a new material slot. if you look in the picture above it shows material 0 which is the material the mesh had before making it a destructible and is collapsed, then theres material 1 which was created after the fracture of the mesh.

The material 1 isn’t being created when I fracture the mesh.