I have a simple Question if i want for example have a tank and i shoot a Bullet, is there any way to make a hole into the ground caused by my bullet hitting the ground?
As far as I know, UE4’s terrain cannot be deformed during runtime (as of yet), so you would have to look at creating your terrain with meshes. Look into Instanced Static Meshes and Hierarchical Instanced Static Meshes. You can create the terrain via Blueprint or C++ and then once that specific mesh is hit remove it (Destroy Actor) causing the hole to appear.
Look around the “Work in Progress” forum, I believe someone made a Minecraft prototype - thats a starting point.
Hope this helps!