3D Scatter Guide

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Understand the scatter library

Scatter authoring is global to the Terrain Atlas biome library rather than stored separately inside every biome inspector. Open the 3D Scatter section in the Vertex 3D Terrain window to create and edit the library.

Create your first scatter object

1. Use the Terrain Atlas pipeline and make sure the terrain has painted biome data.
2. Open 3D Scatter in the Vertex 3D Terrain window. If no profile exists, create the Scatter Library.
3. Choose + Add Scatter Object and give it a clear name such as Meadow Grass.
4. Under Target Biomes, choose one or more biomes from the current library.
5. Start with Density Multiplier 1 on each target.
6. Set the overall Density (clumps per square metre), Spacing, Coverage range, slope, scale and surface alignment.
7. Add a Mesh Variant. Start with the built-in Grass preset or assign a Custom Mesh.
8. Assign or confirm the material, enable GPU Instancing if prompted and use Rebuild Scatter after major changes if the preview has not already refreshed.

Target several biomes from one setup

A scatter object can target any number of Terrain Atlas biomes. The biome picker shows the current biome name and numeric ID. Use + Add Target Biome to extend the list.

At a painted blend, the system evaluates the combined contribution of the scatter object’s targeted biomes. A reusable object can therefore continue across a Grass/Forest boundary instead of requiring separate duplicate definitions.

Accepted instances retain an owning biome based on the contributing target at their position. This is what allows a single reusable grass object to react differently when a live biome modifier affects only one of its target biomes.

Placement controls

Place reeds only along a shoreline

1. Create a Reeds scatter object and target Water only.
2. Use a Coverage range such as 0.15–0.65 to allow reeds where Water blends into Mud, while excluding pure Water at 1.
3. Adjust the painted transition width and range to position the band, then set Density and Spacing for the number and separation you want.

Coverage sums all targeted biomes. If you target both Water and Mud, their combined coverage can be 1 throughout that transition, so the same range will exclude it. Target only the biome whose partial coverage describes the edge you need. Coverage filters eligible surface; the per-biome Density Multiplier changes how many clumps appear there.

Built-in presets and custom meshes

Each scatter object can contain several Mesh Variants. Relative Chance is a relative selection weight, not a percentage that must add to 100. Use different Shape Seed values for variations of a built-in mesh without changing the placement seed. Preset descriptions are available as tooltips.

Shading and surface properties

All built-in presets, including Crystals, have Smoothing Angle: 0–180°. At 0 the faces stay flat; at 180 all adjoining faces can blend their normals. Intermediate values smooth gentle joins while keeping sharper edges. This changes lighting, not the mesh silhouette or terrain’s global Smooth / Sharp setting.

The Vertex Colour Ramp is evaluated from bottom to top locally for each generated element. Smoothness runs from rough at 0 to polished at 1 and defaults to 0.2 for new variants. Metallic controls their metallic response from 0 to 1.

Generated meshes pack Metallic into UV3.R. UV3.G contains the DPT packed scale/roughness value derived from Smoothness, rather than raw smoothness. A custom shader must decode this DPT mesh data to use it correctly.

Emissive scatter

Enable Emissive on a built-in variant, then use HDR colours in its ramp for brightness and ramp alpha for glow coverage. DPT packs that coverage into vertex alpha in the same way as emissive biomes. HDR colour alone does not enable emission. The material’s emission controls still apply; visible bloom depends on the scene’s post-processing, and emission does not create a light source.

Custom meshes

Choose Custom Mesh, assign a 3D Mesh, optional submesh index, Material and optional Distant Mesh. With no Distant Mesh, the near mesh is reused. Custom meshes retain their authored normals, vertex colours and UV3 surface data; the built-in shading, metallic, smoothness and emissive controls do not rewrite them. Enabling supported DPT Scatter Wind prepares a runtime copy with wind/biome data and leaves the source asset unchanged.

Distance, LOD and renderer settings

Expand Scatter Settings. Frequently used controls are grouped under Distance & LOD and Preview & Shadows. Open Advanced for Cell Size, Wind Bounds, per-tile budgets, Up Mode and Runtime Discovery. Placement settings use compact paired sliders, and scale ranges show Min/Max rather than X/Y.

Up Mode and preview

Wind setup

DPT Scatter Wind has two levels of control. The material decides whether the wind feature is active in the shader, while Enable Wind on the Scatter Object decides whether that particular scatter object uses the DPT Scatter Wind path. The Scatter Object control is only available when the assigned shader declares the _DPT_SCATTER_WIND Boolean Keyword, which lets Vertex 3D Terrain recognise that the shader supports this feature.

Using the Vertex Terrain material

1. Open the material’s Wind section and turn on Enable Wind.
2. Set a modest Wind Strength.
3. Set Height To Tip close to the object-space height of the scatter mesh so the base stays anchored and the tip can reach full movement.
4. Choose the Compass Heading and Vertical Pitch.
5. Back in the 3D Scatter section, turn on Enable Wind for each Scatter Object that should use DPT Scatter Wind.
6. If strongly animated tips disappear near the camera or frustum boundary, increase Wind Bounds in Scatter Settings.

Rigid scatter such as pebbles can share the same material while leaving the Scatter Object’s Enable Wind option off.

VCCORE materials

VCCORE uses its own authored wind system, so the Scatter Object’s Enable Wind control is intentionally unavailable for VCCORE materials. This is expected. If wind was painted onto the model with Stylized Color Swapper & Material Optimizer, or the model came from a DPT pack with wind data already authored, no Scatter-specific wind setup is required. Use the VCCORE material’s own wind controls to enable or adjust that movement.

Add DPT Scatter Wind to your own Shader Graph

If your custom shader already has its own wind system, keep using that system. You only need the DPT setup below when you want a custom Shader Graph to use the same Scatter Wind feature as the Vertex Terrain shader.

Open SH_DPT_VCTerrain, copy the Scatter Wind block shown below and paste it into your own Shader Graph. Then add these Blackboard entries using the exact Reference names:

1. Copy the complete Scatter Wind block from the supplied Vertex Terrain Shader Graph and paste it into your graph.
2. Add the four Blackboard entries above if they do not already exist.
3. Reconnect Wind Strength, Wind Direction, Height To Tip and DPT Scatter Wind exactly as shown in the reference image.
4. Connect the final DPT Scatter Wind output to the graph’s Vertex Position input.
5. Save the graph and assign a material that uses it to your Custom Mesh variant.
6. Enable the DPT Scatter Wind keyword on that material, then enable Enable Wind on the Scatter Object.

Live biome density and colour response

The same four Live Biome Modifier slots used by terrain surfaces can also control scatter belonging to their target biome IDs. This lets a seasonal system change the ground and the vegetation together.

For example, a winter slot can increase snow dusting on a grass biome while reducing its Scatter Density and moving its Colour Multiplier toward a pale frosted colour. A reusable grass object can also target a forest biome; those forest-owned instances remain independent unless that biome ID is targeted by the live slot.

See Terrain Material Settings for the material controls and Demo & Runtime Guide for the example controller.

Fade scatter during live changes

1. Open 3D Scatter → Scatter Settings → Distance & LOD.
2. Enable Live Crossfade and start with Fade Range at its default of 0.15.
3. Use a supplied DPT terrain shader with scatter fade support, then animate a live modifier’s Strength or Scatter Density.
4. Adjust Fade Range while watching the transition. Larger values spread each instance’s fade over more of the density animation. Set the animation’s duration and easing in your controller.

Live Crossfade uses dithered visibility: each mesh and its shadow gradually lose or regain coverage as the live population changes. It works with both CPU and GPU scatter rendering and keeps the existing instance positions. At zero live density, the affected scatter and its shadows are fully hidden; reversing the animation fades them back in.

Seasonal snapshots and collapsible profiles

Use the Dynamic Biome Demo Controller to capture material appearances as Environment Profiles. Edit the material, then choose + Capture Current Settings as NEW Profile. Each profile is a saved snapshot; later material edits are saved only when you capture again.

Click a profile’s arrow or name to collapse or expand it. The header keeps its name and sequence position visible, with the first profile marked START. Newly captured profiles open automatically. Expand a profile to edit Name, Transition Seconds, easing and Channels to Animate, or to use its capture, apply, reorder and remove controls. Animate To Profile blends the checked channels from the current appearance and then holds the result.

These rules apply to sequence playback, Edit Mode Preview/scrubbing and Animate To Profile. Each Live Biome Modifier slot supports up to three target biome IDs; this is separate from a Scatter Object’s Target Biomes list, which can contain any number of biomes.

When painting dusting in Scene view, the red dusting preview is drawn before the brush handle, so the selected brush handle colour remains visible over the highlight.

Runtime scatter and baked terrain data

Scatter placement is generated synchronously on the main thread, then cached for rendering. A readable terrain mesh supplies its placement geometry directly. A non-readable terrain mesh can use a matching DPT_TerrainSurfaceData asset with baked scatter geometry instead, so terrain Read/Write does not need to stay enabled for this runtime path.

1. Assign the scatter profile before baking.
2. While the terrain is available for editor authoring, use Bake Surface Data. With a scatter profile assigned, it includes placement vertices, normals, triangles and biome channels as well as gameplay surface information.
3. Keep the baked asset assigned to DPT_TerrainSurfaceTarget on each source terrain and include it in your build.
4. Rebake after terrain geometry, painting, biome IDs or topology change. A gameplay-only or stale bake is not sufficient for scatter placement.
5. Test the built scene with terrain Read/Write disabled. If the renderer requests a scatter geometry bake, supply current data or keep that source mesh readable.

The baked placement arrays consume memory; disabling terrain Read/Write does not eliminate the scatter data itself. Generating or rebuilding a large population can still take main-thread time. This terrain-data option does not remove authored custom mesh requirements, including readable mesh channels when preparing a DPT wind copy.

Performance and practical limits

• Scatter uses GPU-instanced draws rather than one GameObject per instance.
• Placement is generated from the terrain mesh and cached. Ordinary camera movement and live density changes do not rebuild the terrain scatter distribution.
• Camera distance and frustum culling operate on scatter batches/cells. Cell Size therefore affects both grouping overhead and culling precision.
• Far Density can reduce distant population in addition to using a cheaper distant mesh.
• Very high Density on a large terrain can reach the candidate or instance safety caps. Treat those limits as warnings to profile the setup, not targets to maximise.
• Custom meshes should be suitable for instancing and should avoid unnecessary vertex/submesh/material complexity when they will appear thousands of times.

Runtime Discovery is opt-in, so a stable terrain hierarchy does not need a full search every second during play. Built-in variant signatures are cached until the profile changes. Configured mesh caches retain meshes still used by active renderers and release obsolete entries after rebuilds; disabling the final renderer clears the shared scatter caches. Profile changes can still require regeneration.

Scatter problems

Support

If you need help, include your Unity version, the Terrain Atlas biome IDs involved, a screenshot of the Scatter Object and Scatter Settings, the active material and the renderer status line. For placement problems, also mention terrain scale, density and whether the issue occurs on a pure biome or a blend.

Use the DPT Games contact form or join the DPT Games Discord.

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