# Unreal mapping note

The prototype stores a two-channel height and vertical-velocity field in a pair of
`RG32F` textures. A world-owned Unreal component could keep equivalent transient
render graph textures and advance them with a compute pass. It should own simulation
time and clear or restore its buffers when the world is recreated.

The sphere path becomes a world-space interaction event: position, contact radius,
and impulse strength are supplied to the compute pass. For multiplayer or deterministic
replay, replicate the compact events and simulation tick, or record the resulting field;
do not assume that independent GPU floating-point runs will produce byte-identical
textures.

The rendered top surface can remain a render-only displaced mesh. If it must participate
in voxel collision or queries, its height must also reach the density evaluator. For a
height `h(x,y)`, the plugin's density convention is negative inside solid and positive
in air, so the plane's signed density is `z - h(x,y)`. Keep this calculation in metres
until the existing voxel/Core boundary converts with the active voxel size (25 cm by
default); do not mix metre distances and voxel counts in the wave solver.

The current sample is an isolated visual field. Wiring this into `AVoxelWorld` would
need an explicit owner for simulation lifetime, collision/update cadence, save/load,
and the replication policy before it could affect shipped terrain.