What version of the engine are you using? If you’re using 4.5.1 or earlier I would recommend using the 4.6 preview until 4.6 is fully released here soon. There have been some great changes with Destructible Meshes like getting the chunk parameters to function properly now.
I have a sample project I made for another user to test and posted that in the community tutorials section at this link: https://forums.unrealengine.com/showthread.php?52865-Sample-Project-to-destroy-Destructible-Mesh-with-Line-Trace-and-Ball-projectile
In this sample project I made two types of projectiles. A line trace that will apply a radial damage at the hit location of the trace and the other is the yellow ball projectile from the FPS Template.
You will need at minimum the 4.6 preview (which you can download from the launcher) to open the project.
With all that said let’s dive into some of your issues you’re having.
When you reply back can you suggest/show a shape of the object you’re trying to create the fractures for, along with the fracture Cell Site Count? With this I can then start trying some rough settings to better suggest more specific results.
From your description with this problem it seems to me that you’re using the FPS template projectile with the yellow ball, correct? For something like this I would probably suggest adjusting the mass for the DM itself but there is a known issue with mass not functioning properly for DMs (UE-5642).
Needless to say there are probably some settings here that can be adjusted to give you better results. Let me know if you’re using the ball projectile (which will give you the least accurate results) or the line trace projectile and I can suggest some things that may or may not work in your case.
Provide the information I’ve requested above and I can suggest some things that may work in your case.
There are a couple of things with this. For the first part where you want smaller chunks to break apart. This is not possible with the fracture tool in the engine. There is only one layer of depth that is provided stock. If you want to have multiple fracture levels (ie. shoot a pile on a wall, a large chunk falls and fractures into smaller pieces when shot or hitting the ground) you’ll need to use PhysX Labs. There is the standalone application for PhysX Labs or you can get the 3Ds Max/Maya plugin. The can be grabbed from Developer.Nvidia.com for free once you signup with an account. Well worth it in my opinion as you can get much more control over your mesh and choose how you want your mesh to fracture based on image masks rather than just a Voronoi method.
Here are some of their tutorials to give you a better idea:https://developer.nvidia.com/apex-destruction-physxlab-tutorials
Specifically take a look at the second video for cutout fracturing to see what I mean.
For the second part, there are a couple of ways to handle debris timeout. Again, depending on how the mesh is setup you can have all the chunks disappear after a set time or fade out between two specified times. The second option requires a few more settings tweaks but is possible.
Here is a settings setup to get the chunks to fade over time:
I used these settings for my line trace weapon. I have not tested them with the projectile ball. Results may vary for the destruction.
I’ll look into this one and see if I can offer any feedback.