Multiple species

Kiwi Grass 26.8.0 keeps the existing one-species workflow as its compact default and supports up to four active species in advanced Field Composition.

simple mode

Leave Multiple Species disabled to retain the compact one-species placement, fingerprint, format-2 persistent bake, material, command, and update path. Primary species ID 1 is reserved and does not need to be authored.

advanced fields

Enable Multiple Species under Setup > Field Composition. The existing renderer layer and look remain the primary species. Each additional entry exposes:

• Stable ID: a unique value of 2 or greater. Identity follows this value rather than array position.
• Terrain Layer: the painted terrain layer that supplies this species coverage.
• Grass Profile: blade shape, material, natural variation, and lighting.
• Density Share: a relative share of the existing total field density and maximum-blade cap.
• Minimum and Maximum World Height: an optional altitude band.
• Maximum Slope Degrees: a species-specific slope ceiling.
• Wind Stiffness: 0 keeps the profile's complete wind response; 1 removes wind displacement for that species.
• Interaction Response: 0 ignores shared stomp bend and flatten strength, 1 uses the profile response, and values through 2 amplify it within normal stomp limits.
• Enabled Quality Levels: independent High, Medium, and Low participation. Off disables the complete renderer.

Only valid enabled entries with a positive density share participate. Disabling an entry or excluding it from the current quality level removes its share and renormalizes the remaining active species.

budgets and runtime ownership

Density shares never multiply the renderer budget. If the renderer is configured for 42 blades per square meter and a 2,000,000 maximum blade count, the active species divide those same totals. Integer capacity allocation is deterministic, assigns at least one slot per active species, and never exceeds the configured combined cap.

The field shares terrain presentation, the control map, dirty tracking, one culling pass, the stomp texture, runtime blade buffers, Hi-Z history, and the draw-buffer pool. Each species owns contiguous chunk, blade, and indirect-command sections. Commands are submitted by species and geometry LOD with that species' material. The runtime blade remains the same species-agnostic 24-byte record.

Per-species diagnostics report stable ID, blades, reserved capacity, chunks, visible commands, blade bytes, and active draw bytes. Their blade, chunk, command, and blade-memory values sum to the renderer totals.

bundled starting points

Actions > Field Composition > Apply Two-Species Meadow keeps the primary grass at 84% and adds sparse Tall Wild Grass at 16%.

Actions > Field Composition > Apply Four-Species Stress keeps the primary grass at 68% and adds Tall Wild Grass, Dry Field, and Silver Pampas at 14%, 10%, and 8%. This is a combined-budget stress composition, not a recommendation that every production field needs four materials.

Both actions bind the added profiles to the current primary TerrainLayer so they work without changing terrain paint. Assign another TerrainLayer per entry when species should follow distinct painted coverage.

updates and persistence

One-species terrain and Artist Control placement edits retain bounded dirty-chunk patching. With multiple species active, placement-affecting edits request a safe complete-field regeneration so every contiguous species section commits from the same terrain revision. Shader-only field changes remain presentation updates.

Formats 1 and 2 load as one primary species. One-species writes remain format 2. Two-to-four-species writes use format 3 and validate stable IDs, profile and material identity, contiguous ranges, and combined totals. Enabling advanced composition makes an incompatible one-species bake stale and regenerates it; incompatible data is never reinterpreted as multiple species.