Procedural meshes for non-rectangular shapes?

So I started playing with procedural meshes lately in my attempts to re-create a level and some vehicle from farming simulator in UE4. I got trailers and tractors handled (as well as PhysX 3.3 will allow) but now I want to fill them with something. The game engine uses whats called a fill plane and does what it says, its a plane that fills (procedurally… certain parts of the plane “heap up” depending where the ‘fill’ is coming from.)

The math hurts my head so much I can pretty much only get a box scaling in the Z what I beleive to be proper by using Get Bounds of the procedural mesh component and then adding lcoal offfset in the Z by that amount every frame as much as I increase the Z value each frame.

So I could simulate filling a square trailer from bottom to top with enough work but thats kindve boring.

How could I simulate this effect which is as described above. Even triangles would be a great start. I remember seeing some of this stuff in ramas plugin thread it seems there just isnt enough stock BP nodes.

Are there any algorithims that I could use to create arrays for the create/update mesh parts of procedural meshes or are we talking getting into C++ and complex stuff here? I’ve read all the threads where people make mathematical shapes and “pretty colors” and such but looking for more utilitarian uses here.

Jump to 2:50 to see the effect or click here

So this is as far as I was able to get. Due to my trailer needing to simulate physics (due to unreal/physX’s terrible vehicle implementation out of the box) because the wheels and hitch are just constraints its very buggy and as you can see theres issues rotating the fill plane to the rotation of the trailer as well its not going to the bottom of the trailer unlike my test scene where it grew up from the floor.

Anyone have any tips? Most likely would I have to extend the UProceduralMeshComponent class? I have a couple months left of Java 100 in uni before I even get to c++ 100