Quick answer: Unreal Niagara Grid2D data interface losing data when grid resolution changes? Resolution change is destructive - cache contents and restore, or design around fixed resolution.
Fluid sim Grid2D resolution slider clears the simulation each adjustment. Players can't iterate.
Cache contents pre-change
Read the grid via GetCellValue into a CPU buffer. Resize. Write back via SetCellValue with interpolation.
Or fix the resolution
For shipping, freeze the resolution. Quality is fixed; bugs are eliminated.
Use a side-channel cache
Maintain the grid contents in a SystemSimulation parameter. Re-initialize from the parameter after resize.
“Grid2D is a GPU resource. Resize is allocate-new-clear; not copy-preserve.”
For simulation grids, resolution should be a launch-time decision. Mid-game changes are a deep refactor; not a slider toggle.