Instanced Static Mesh Array System for Unreal Engine

World Arrays (ISM) is an Unreal Engine plugin that lets you create
automatic X, Y, Z, 2D, or 3D arrays of Instanced Static Meshes with
built-in helpers for:

Automated array construction
Per-instance custom data (materials, progress bars, animations)
Percentage-based activation
Max instance caps
Random jitter & overrides
Blueprint and C++ extensibility