Why are Impulses and forces not working on destructible components?

I’ve spent 2 days messing with settings. the only functions that work are apply radial force and apply radial impulse. the others get ignored. I’m especially interested in applying physics to the chunks.

If there is a way to apply linear forces / impulses please let me know what your settings and blueprint look like.
also, Im not looking to apply forces on damage, but rather after and before the fracture.

For context, picture a nicely furnished room with music that is so loud that everything shakes. as things hit the floor they shatter and continue to rumble with the bass.

From your description it sounds as if you need your meshes to have more than one support depth for destruction. If you’re creating your destructible in UE4 you’ll only be able to have one support depth. This means that Depth 0 will be no destruction and depth 1 will be destroyed. If you use Nvidia’s PhysXLabs standalone app or their plugin for 3Ds Max/Maya you can set different support layers for the destruction.

Setting up something like:
Depth 0: no destruction
Depth 1: slight destruction
Depth 2: full destruction

These can be tweaked and set through the PhysXLabs or further tweaked in UE4 with all the depths.

The individual pieces will react to the environment and any forces and impulse as well.

You can find more information about Nvidia’s destruction on their site at Developer.Nvidia.Com

If you have any questions about getting your destructible setup feel free to ask.


That doesn’t sound quite right to me.
I decided to reproduce this in an isolated setting.
please tell me if you notice anything obviously wrong.

First, I took SM_Vase_1 from the realistic rendering demo and converted it to a destructible mesh. I set the count to 25 and fractured it to have 2 depths.
then I changed impact damage to 1 and default impact damage depth to 1 and saved.

Next I created a new blueprint with just this destructible component.
I made sure simulate physics is on, and that collisions are preset to destructible and generate hit and overlap events.

next here are my results:

EDIT: This doesnt seem to let me post more images so here is a link:

Radial Impulse:
the radial impulse makes the vase move. it will also make the chunks move. this is great.

I literally slid down the radial impulse and attached impulse. the vase will move, but once it fractures, nothing happens. hence why i believe its a bug.

as for my input there, I happen to be using my audio analisis plugin, but you can use a timer. every half second or so a dance song beat triggers the impulse. I have a force of 500. I’ve tried putting in 9999 and there’s no difference when its not radial.

for the pics, above, I moved the vase up a meter or so and let it drop so it shattered. but rest assured I tried this with the vase before and after fracture. in my opinion there is something wrong with “add impulse” and also with “add force”. try them all. only the radial variants ones work on the chunks.

With your setup I’m not sure if this is expected behavior or not. I will follow up with a developer. I did, however, setup a radial force in my BP components that was deactivated and then activated in my event graph to fire. This may be a workaround if in-fact the other node is bugged.

With your destructible mesh though you can only have one layer of destruction setup by using the fracture tool in UE4. There is depth 0 which is no destrution and depth 1 which is full destruction. For any other layers you’ll have to use an external software.