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Randomization

Laying out multiple same meshes can look repetetive. To break repetition you can use a couple of approaches: mesh variation and material variation.

  • Use mesh variation to swap, mirror, rotate, or knock out meshes.
  • Use material variation to introduce random tiling, color shifts, and grunge effects.

1. Randomization with Mesh Variations

Mesh randomization allows you to replace “key meshes” with random alternatives, mirror them, or rotate them to break repetition.

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FRandomMeshes Parameters

Parameter Description
KeyMesh – The mesh that will be replaced by one from the RandomMeshes array (including the KeyMesh itself).
RandomMeshes – An array of meshes with weights (FRandomMeshWithWeight). A higher weight increases the chance of being selected.
FitRandomType – MatchScale or KeepScale – whether the new mesh scales to fit the original or keeps its own scale.
Knockout – How many meshes are randomly removed (0.0f = none, 1.0f = all).
MirrorX / MirrorY / MirrorZ – Randomly mirror the mesh on that axis. Only works when baking to StaticMeshComponents.
Rot90 – Randomly rotate by 90, 180, or 270 degrees.
Rot180 – Randomly rotate by 180 degrees.

2. Randomization Inside Materials

Another way to break up repetition is to add variation inside the material itself, using world-space position or per-instance random values as a seed.

Material Randomization Examples

You can use per-component seeds for small variations (e.g. random damage decals, grunge masks) and per-actor seeds for large-scale variation (e.g. different building colors).

Examples from materials:

  • Per-Instance Random or Component Pivot Location can be used to shift UVs, distort tiling, or randomize texture offsets.
  • Actor Position can be used as a seed to shift hue or other color variations per-building.

Randomizing storefront banner color with Per-Component seed.

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Randomizing building color with Actor Position as a seed.

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