Grass, foliage, and PCG

Choose one owner per population

Need	Default system	Boundary
Material/paint-driven passive ground cover	Landscape Grass Output + Landscape Grass Type	Works only with Landscape terrain; coupled to material layer weights
Hand-authored instance painting	Foliage Mode + Static Mesh Foliage	Efficient instancing and direct art control
Ecological offline simulation	Procedural Foliage	Experimental editor workflow in current documentation
Rule-driven spatial generation, exclusions, runtime generation	PCG	Route graph implementation to $unreal-pcg
Unique behavior/identity	Actor or PCG Spawn Actor	Costs like actors; keep density low

Do not simultaneously generate the same grass/tree class through Landscape Grass, Foliage, and PCG. Establish ownership, exclusion, regeneration, and source-control policy.

Landscape Grass workflow

1. Derive a mask from a named Landscape Target Layer using LandscapeGrassOutput.
2. Create a Landscape Grass Type and entries for meshes, density, scale, rotation, alignment, and cull distances.
3. Attach the Grass Type to the corresponding Grass Output input.
4. Paint/fill the driving Landscape layer.
5. Validate density, collision expectations, shadows, wind, LOD/Nanite, and culling in a cooked build.

Landscape Grass is appropriate for passive visual distribution. If individual plants need durable identity, interaction, or authoritative state, they are not merely grass instances.

Foliage Mode workflow

• Prefer Static Mesh Foliage for decoration; it is hardware-instanced and batched.
• Actor Foliage has the rendering/gameplay cost of ordinary actors. Use only where behavior requires it.
• Define slope, height, scale, alignment, collision, density scaling, cull distance, shadow, and navigation impact in governed Foliage Type assets.
• Use Reapply deliberately; it can change many existing instances.
• Validate instance attachment after Landscape edits and choose the UE 5.8 foliage snapping behavior intentionally.

Procedural Foliage

The current guide still places Procedural Foliage under Experimental editor settings. Use it only after validating plugin availability, resimulation determinism, source-control output, cook behavior, and iteration cost.

Performance and gameplay

• Use foliage.DensityScale only for types configured to participate in scalability.
• Cull distances, LOD/Nanite, shadow policy, WPO/wind, overdraw, and material cost determine final expense—not draw calls alone.
• Collision on dense small foliage is usually wasteful; collision/navigation blockers on important trees require explicit testing.
• Rebuild or update navigation after collision-relevant vegetation changes.
• Treat visually dense forests as AI sightline and path-design content, not only rendering content.

Acceptance

• no duplicate ownership;
• deterministic regeneration where required;
• no vegetation on roads, entrances, traversal clearance, or critical sightlines;
• expected collision/nav/physical-surface behavior;
• stable memory and frame time through density scalability extremes;
• no visible cull/LOD transition beyond the project's budget.