Artist details Nanite Assemblies vegetation workflow behind Alpine Forest in UE5

Michael Gerard, a freelance biome artist, spoke to 80 Level about Alpine Forest, a Unreal Engine 5 environment that began as a technical test. His goal was to get vegetation from SpeedTree into Unreal Engine as Nanite Assemblies, without passing through another DCC application. He chose coniferous trees on purpose, calling them one of the biggest challenges for Nanite in vegetation.

To do this he developed SpeedTree Bridge. He says SpeedTree remains central to his vegetation creation, and the Bridge gives him a more direct path into the engine while preserving what he likes about building with Nanite Assemblies. He describes the Assemblies approach as building complex assets from instanced geometry that keeps more of the original structure, rather than relying on simplified stand-ins for volume. He also says Nanite Assemblies are not a universal solution: how well they work depends on vegetation structure, materials, animation and scene complexity. He recently set up FoliageLab, a studio focused on real-time vegetation, biome production and specialized tools.

On the art side, most larger trees started from scanned trunks from ScansLibrary, which he turned into tileable textures with SpeedTree's built-in tools. Foliage instances are shared across several species, using the same geometry, textures and materials. Each tree has its own Material Instances for the trunk, all based on a single Master Material. Variation comes from structure, size, silhouette and distribution rather than heavy material changes.

For placement, he reworked three PCG systems: Trees, Bushes and GroundFoliage. Trees now influence where bushes go, and bushes influence ground foliage. If there are no bushes, the trees drive ground foliage directly. He says PCG sets a consistent foundation while he keeps manual control over density, distribution and local variation.

The lighting is simple and entirely dynamic: a Directional Light, SkyAtmosphere, and a SkyLight using a neutral white HDRI. Most of the cold, overcast mood comes from fog, made with the Screen Space Fog Scattering plug-in. Post-processing is limited to a custom LUT and a small amount of film grain. The final output is a set of short cinematic sequences showing the forest from different angles.