3D Terrain Graph

The Terrain Graph Editor is a visual, node-based tool for designing procedural terrain in Voxel Play 4. Instead of writing code, you connect nodes on a canvas to build a signal-processing pipeline that generates, transforms and blends values into a complete voxel world with biomes, caves, water and vegetation.

This page is a comprehensive reference for the Graph Editor window, all toolbar options, and every available node type with its parameters and formulas.

Two Graph Systems

Voxel Play 4 includes two terrain graph editors:

	Terrain Graph (2D)	3D Terrain Graph
How it works	Generates a heightmap (altitude + moisture). Terrain is solid below the height, air above.	Generates a 3D density field. Terrain exists wherever density > 0, enabling caves, overhangs and floating islands.
Outputs	Altitude, Moisture	Density, Voxel ID, Vegetation ID, Tree ID, Water ID
Generator asset	Multi-Step Terrain Generator	3D Density Terrain Generator
Best for	Classic heightmap worlds, simpler setup	Complex worlds with caves, arches, volumetric features

Getting Started

Step 1: Create a Generator Asset

In the Project window, right-click and choose:

• Create > Voxel Play > Terrain Generators > Multi-Step Terrain Generator for 2D
• Create > Voxel Play > Terrain Generators > 3D Density Terrain Generator for 3D

Name it something descriptive (e.g. "MyWorldTerrain").

Step 2: Open the Graph Editor

Double-click the generator asset to open the visual editor. Alternatively, use the menu Window > Voxel Play > Terrain Graph Editor or 3D Terrain Graph Editor.

Step 3: Build Your Graph

Right-click in the graph area (or press Ctrl+Space) to open the node search menu. Add nodes by category:

1. Start with a noise sampler (e.g. Noise 3D, Sample Fractal) to generate base terrain shape
2. Add a Height Gradient node (3D only) to define where solid meets air
3. Use math and blend nodes to combine, scale and shape the output
4. Add a Cave Carver to hollow out underground areas
5. Connect a Climate Map node for biome-aware voxel selection
6. Wire the final result to the output terminals on the right side of the graph

Step 4: Assign to Your World

In your World Definition asset, set the Terrain Generator field to your generator asset. Press Play to see the result.

Window Layout

The editor window is divided into the following areas:

Toolbar

The top toolbar contains buttons and toggles:

Control	Type	Description
New	Button	Creates a new terrain generator asset and opens it in the editor.
Reload	Button	Reloads the graph from the saved generator asset, discarding any unsaved changes.
Save	Button	Saves the current graph state to the generator asset. Also available via Ctrl+S / Cmd+S.
Auto Layout	Button	Automatically arranges all nodes in a clean layout based on their connections.
Fit View	Button	Zooms and pans the canvas so all nodes are visible.
Minimap	Toggle	Shows or hides the minimap overlay (top-left corner). Shortcut: M.
Preview	Toggle	Shows or hides the terrain preview panel.
Diagnostics	Toggle	Shows or hides the diagnostics panel that reports errors, warnings and info messages about the graph.
Sync	Toggle	When enabled, the editor monitors the graph output and automatically refreshes the scene world whenever the terrain changes. Enabling Sync also performs an immediate world update.
Update World	Button	Manually reloads the currently loaded world using the current graph state.

Canvas

The main area where nodes are placed and connected. Navigation:

• Scroll wheel: zoom in/out.
• Middle-click drag or Alt + drag: pan the view.
• Right-click on empty space: opens the Create Node search menu.
• Click a node to select it. Shift+click or drag a selection box for multiple nodes.
• Delete / Backspace: delete selected nodes and connections.
• Ctrl+C / Ctrl+V: copy and paste selected nodes.
• Ctrl+Z / Ctrl+Y: undo and redo.

Minimap

A small overview in the top-left corner showing the full graph layout. Click or drag inside the minimap to navigate quickly to any part of the graph. Toggle its visibility with the M key or the Minimap button in the toolbar.

Preview Panel

The preview panel (bottom-right by default) renders a real-time visualization of the terrain produced by the current graph. It can be dragged to reposition and resized by dragging its edges.

The preview offers the following display modes:

Mode	Description
Hillshade	Default mode. Shaded relief view of terrain elevation with simulated lighting; water areas shown in blue.
Heightmap	Color-coded altitude: blue for water, green for land, white for peaks.
Moisture	Visualizes the moisture output. Requires a Moisture Output connection in the graph.
Biomes	Colors each pixel based on the biome selected by the altitude/moisture combination. Requires a World Definition with biomes configured.
Horizontal Slice (3D only)	Cross-section of the density field at a given Y height.
Vertical Slice (3D only)	Side-view cross-section of the density field.

Adjust the preview resolution (32-512 px) and, for the 3D slice modes, use the Slice Y slider to choose the cross-section height. The status bar at the bottom of the preview shows altitude range, coverage area, and water level. Click on the preview to inspect altitude and moisture values at a specific world position.

Diagnostics Panel

When enabled, the diagnostics panel appears at the bottom of the window. It shows real-time validation messages about your graph:

• Errors (red): issues that prevent the graph from producing valid output (e.g., disconnected output nodes, cycles).
• Warnings (yellow): potential problems that may cause unexpected results (e.g., unconnected input ports).
• Info (white): general information about the graph state.

Click on a diagnostic message to highlight the affected node in the canvas.

Working with Nodes

Creating Nodes

Right-click on the canvas (or press Ctrl+Space) to open the Create Node search menu. Nodes are organized into five categories, each with a distinct color:

Category	Color	Description
Samplers	Green	Generate initial terrain values from noise textures, fractal noise, Unity Terrain data, constants or random values. These nodes have no required inputs - they produce values from external sources or fixed data.
Math	Orange	Transform values using arithmetic, range manipulation, and terrain-shaping functions. Includes single-input operations (shift, clamp, remap) and dual-input operations (min, max, subtract, divide).
Blending	Purple	Combine two input values using additive or multiplicative blending with custom weights.
Filters	Yellow	Conditional operations: threshold comparisons, range tests, value replacement, and special-purpose masks.
Utilities	Gray	Helper nodes like Reroute for organizing complex connection layouts.

Connecting Nodes

Each node shows input ports on the left and an output port on the right. To connect nodes, drag from an output port to an input port (or vice versa). Values flow through connections and are evaluated in topological order.

Port names vary by node type:

• Out: the single output port present on every step node.
• In: a single input for nodes that transform one value (e.g., Shift, Invert, Clamp).
• A / B: two inputs for dual-input operations (e.g., Blend Additive, Min, Max, Subtract).
• Value / Ref or Value / Mask: nodes like Fill and Beach Mask that carry a main value through while reading a separate reference input.

Output Nodes

In the 2D Terrain Graph, the graph has two special output nodes that cannot be deleted:

• Altitude Output: the final terrain height value (normalized 0 to 1). This value is multiplied by Max Height to determine the world altitude in voxels.
• Moisture Output: an optional secondary value used together with altitude for biome selection. If no connection is made to Moisture Output, the terrain generator falls back to the legacy moisture texture configured in the Inspector.

The 3D Terrain Graph exposes a different set of output terminals - see 3D Graph Outputs below.

Node Controls

• Enable/Disable toggle: the checkbox in the node title bar. Disabled nodes are dimmed and skipped during evaluation.
• Custom description: each node has a description field (right-click the node and choose Rename to set it). When set, it replaces the default operation name in the title bar, helping you label nodes by purpose (e.g., "Base Mountains", "River Mask").
• Collapse/Expand: click the node title to toggle parameter visibility.

Height Units

Many numeric parameters support three display modes via a dropdown next to the field:

Unit	Description
Normalized	Raw graph value, typically in the 0..1 range. This is the internal representation.
Percentage	The normalized value multiplied by 100. Entering 50% is equivalent to 0.5 normalized.
Meters	Converts using the terrain generator's Max Height. For example, with Max Height = 255, entering 127.5 meters equals 0.5 normalized.

The unit choice is purely a display convenience - the internal stored value is always normalized. Changing the unit dropdown converts the displayed number without altering the actual parameter.

Reroute Nodes

Reroute nodes are small pass-through dots available in the Utilities category (right-click > Create Reroute). They have one input and one output and simply forward the value. Use them to organize connection lines in complex graphs - route wires around obstacles or create cleaner visual paths. Reroute nodes can branch: a single input can feed multiple outputs.

Node Groups

Select several nodes, right-click and choose Create Group to wrap them in a titled box. Rename the group to label a stage of the graph (for example "Heightmap", "Caves" or "Climate") and move its nodes together. Right-click a group and choose Ungroup to dissolve it.

3D Graph Outputs

The 3D graph has five output terminals:

Terminal	Type	Description
Density	Required	Volume density. Positive = solid voxel, negative = air, zero = surface.
Voxel ID	Optional	Biome index for selecting which block type to place (connects to biome array)
Vegetation ID	Optional	Biome index for grass/flower placement
Tree ID	Optional	Biome index for tree generation
Water ID	Optional	Water presence flag (positive = place water)

ID outputs reference the biome array in your World Definition. For example, if Voxel ID outputs 2, the engine uses the voxel definitions from biomes[2].

Performance

The graph evaluation includes automatic optimizations:

• Column caching - 2D nodes (noise that only depends on X/Z) are evaluated once per column and cached, avoiding redundant computation across the vertical axis. Up to ~10x speedup for 2D-heavy graphs.
• Multi-core parallelization - 3D evaluation uses Parallel.For with per-thread workspaces. Typical ~5x speedup on modern CPUs.
• All-air fast path - Chunks that produce only air are detected early and skipped entirely.

Tip: Prefer 2D noise nodes over 3D noise nodes when the result doesn't need to vary with altitude. The column cache only works for 2D nodes.

Min Island Width (Island Filter)

3D density fields can leave tiny floating islands wherever the noise barely crosses the surface threshold. The Min Island Width option on the 3D Density Terrain Generator (minIslandWidth, 0-64, default 0 = disabled) removes isolated solid clusters narrower than the given number of voxels across (their largest horizontal extent in X or Z).

• The filter is deterministic and applied consistently everywhere the terrain is evaluated: painted chunks, the distant Super Chunks LOD and detail generators.
• Only floating clusters are affected - columns connected to the ground are never removed.
• Very large components are always kept (the measurement is capped, fail-open), so the filter cannot eat real islands.

Node Reference

This section documents the core sampler, math, blending, filter and utility nodes with their parameters, input/output ports, and evaluation formulas. The 3D Terrain Graph adds volumetric nodes such as Height Gradient, 3D noise and the Cave Carver; the Node Reference page lists the complete node set.

Samplers (Green)

Sampler nodes generate initial terrain values. They have no required input connections.

Sample Height Map Texture

Reads a value from a repeating 2D noise texture. The red channel is used as the height value. Voxel Play 4 includes several noise textures in Resources/Worlds/Earth/Noise/, but you can provide your own.

Parameter	Description
Noise Texture	The 2D texture to sample. The red channel provides the height value.
Frequency	Multiplier applied to world X/Z coordinates before sampling. Higher values make the pattern repeat more often (default: 0.1).
Offset	X/Z offset added to sampling coordinates before reading the texture.
Min	Lower bound of the remapped output range.
Max	Upper bound of the remapped output range (default: 0.5).

Formula: output = sample(texture, x * frequency + offsetX, z * frequency + offsetY) * (max - min) + min

Sample Ridge Noise From Texture

Similar to Sample Height Map Texture but applies a ridge formula to the sampled value: 2 * (0.5 - abs(0.5 - value)). This produces sharper, more acute relief patterns - useful for generating rivers (when inverted) or pointy mountain ridges.

Parameter	Description
Noise Texture	The 2D texture to sample.
Frequency	Sampling frequency multiplier.
Offset	X/Z offset added to sampling coordinates.
Min	Lower bound of the remapped output range.
Max	Upper bound of the remapped output range.

Formula: ridged = 2 * (0.5 - abs(0.5 - sample)), then output = ridged * (max - min) + min

Sample Height Map Fractal

Generates procedural Perlin fractal noise without requiring a texture. This is the most flexible sampler for creating natural-looking terrain, as it combines multiple octaves of noise at different frequencies.

Parameter	Description
Frequency	Base frequency of the fractal noise. Higher values produce more frequent variation.
Octaves	Number of fractal layers combined together (1-8). More octaves add finer detail.
Persistence	Amplitude multiplier from one octave to the next. Lower values reduce the contribution of higher octaves.
Lacunarity	Frequency multiplier from one octave to the next. Controls how quickly detail increases.
Min	Lower bound of the remapped output range.
Max	Upper bound of the remapped output range.

Formula: output = fractalNoise(x, z, frequency, octaves, persistence, lacunarity) * (max - min) + min

Sample Height Map Unity Terrain

Reads height data from an existing Unity Terrain asset's heightmap. Useful for converting a hand-painted Unity terrain into a Voxel Play 4 world while combining it with procedural operations.

Parameter	Description
Terrain Data	The Unity TerrainData asset to sample.
Frequency	Multiplier applied to world X/Z before sampling. Higher values repeat the terrain data.
Offset	X/Z offset added before reading the heightmap.
Min	Lower bound of the remapped output range.
Max	Upper bound of the remapped output range.

Constant

Outputs a fixed constant value. Useful as a baseline height, a weight input, or any fixed parameter that other nodes can reference.

Parameter	Description
Value	The constant value to output. Supports height units (Normalized/Percentage/Meters).

Random

Outputs a deterministic pseudo-random value in the 0-1 range based on the world X/Z position. The same position always produces the same value, ensuring consistent terrain generation.

No parameters.

Math (Orange)

Math nodes transform incoming values. Single-input nodes have one In port. Dual-input nodes have A and B ports.

Shift

Adds a constant amount to the incoming value. The simplest way to raise or lower the entire terrain.

Port/Parameter	Description
In (input port)	Value to shift.
Add	Amount added to the input. Supports height units.

Formula: output = input + Add

Invert

Flips the incoming value. Mountains become valleys and valleys become mountains.

Port	Description
In (input port)	Value to invert.

Formula: output = 1 - input

No parameters.

Add And Multiply

Adds a number to the input then multiplies the result. Useful for shifting and scaling a signal in one step.

Port/Parameter	Description
In (input port)	Value to transform.
Add	Amount added before multiplication. Supports height units.
Then Multiply	Factor applied after adding.

Formula: output = (input + Add) * ThenMultiply

Multiply And Add

Multiplies the input then adds a number. The reverse order of Add And Multiply.

Port/Parameter	Description
In (input port)	Value to transform.
Multiply	Factor applied to the input.
Then Add	Amount added after multiplication. Supports height units.

Formula: output = (input * Multiply) + ThenAdd

Exponential

Raises the input to a power. Useful for accentuating valleys (exponent < 1) or sharpening mountain peaks (exponent > 1). Negative input values are clamped to 0 before exponentiation.

Port/Parameter	Description
In (input port)	Value to exponentiate.
Exponent	Power to raise the input to.

Formula: output = max(input, 0) ^ Exponent

Remap

Linearly remaps the incoming value from a source range into a target range. Values outside the source range will extrapolate beyond the target range - chain a Clamp node after Remap if you need to limit the result.

Port/Parameter	Description
In (input port)	Value to remap.
From Min	Lower bound of the input range. Supports height units.
From Max	Upper bound of the input range. Supports height units.
To Min	Lower bound of the output range. Supports height units.
To Max	Upper bound of the output range. Supports height units.

Formula: t = (input - FromMin) / (FromMax - FromMin), then output = lerp(ToMin, ToMax, t)

Abs

Outputs the absolute value of the input. Useful for converting signed noise into unsigned values, or creating symmetrical terrain patterns.

Port	Description
In (input port)	Value to take the absolute of.

Formula: output = abs(input)

No parameters.

Terraces

Quantizes the incoming value into discrete terrace bands, creating a stepped, plateau-like terrain effect. The smoothness parameter controls how soft the transitions are between bands, and the strength parameter blends between the terraced result and the original input.

Port/Parameter	Description
In (input port)	Value to terrace.
Steps	Number of terrace bands generated across the value range (2-64). Default: 6.
Smoothness	How soft the transitions are between terraces (0-1). 0 creates hard steps, 1 creates very smooth blending. Default: 0.2.
Strength	Blend between the original input and the terraced result (0-1). 0 means no terracing, 1 means full terrace effect. Default: 1.

Formula: terraced = applyTerraces(input, steps, smoothness), then output = lerp(input, terraced, strength)

Flatten Or Raise

Modifies terrain slope above a threshold. If the input is above Min Elevation, the excess above that threshold is multiplied by a factor. Values below the threshold pass through unchanged.

Port/Parameter	Description
In (input port)	Value to modify.
Min Elevation	Threshold above which the terrain slope is modified. Supports height units.
Multiplier	Slope factor applied above Min Elevation. Use 0 to flatten to the threshold, 1 to keep unchanged, >1 to exaggerate.

Formula: if input >= threshold: output = (input - threshold) * multiplier + threshold, else output = input

Clamp

Constrains the input value to a given range. Values below Min are raised to Min; values above Max are lowered to Max.

Port/Parameter	Description
In (input port)	Value to clamp.
Min	Lower clamp bound. Supports height units.
Max	Upper clamp bound. Supports height units.

Formula: output = clamp(input, min, max)

Min

Outputs the smaller of two input values. Useful for combining terrain layers where you want the lower elevation to win.

Port	Description
A (input port)	First value.
B (input port)	Second value.

Formula: output = min(A, B)

No parameters.

Max

Outputs the larger of two input values. Useful for combining terrain layers where you want the higher elevation to win.

Port	Description
A (input port)	First value.
B (input port)	Second value.

Formula: output = max(A, B)

No parameters.

Subtract

Subtracts the second input from the first. Useful for carving features out of a base terrain.

Port	Description
A (input port)	Value to subtract from.
B (input port)	Value to subtract.

Formula: output = A - B

No parameters.

Divide

Divides the first input by the second. If the divisor is zero or nearly zero, the output becomes 0 to avoid invalid values.

Port	Description
A (input port)	Dividend.
B (input port)	Divisor.

Formula: output = |B| > 0.000001 ? A / B : 0

No parameters.

Island

Creates an island falloff by reducing terrain height based on distance from the world origin (0, 0). Beyond the configured radius, height decreases progressively, creating natural island boundaries.

Port/Parameter	Description
In (input port)	Terrain height value to modify.
Radius	Island radius in world units. No height reduction occurs inside this radius.
Slope Multiplier	How strongly terrain is lowered beyond Radius. Higher values create steeper coastal drops.

Formula: d = sqrt(x*x + z*z) - Radius. If d > 0: output = input - d * SlopeMultiplier / MaxHeight, else output = input

Blending (Purple)

Blending nodes combine two input values into one.

Blend Additive

Combines two inputs with custom weights. The most common way to mix different terrain layers (e.g., base terrain + mountain overlay).

Port/Parameter	Description
A (input port)	First input value.
B (input port)	Second input value.
Weight A	Multiplier applied to input A before summing (default: 1).
Weight B	Multiplier applied to input B before summing (default: 1).

Formula: output = A * WeightA + B * WeightB

Blend Multiply

Multiplies two input values together. Useful for masking one terrain signal with another - for example, multiplying a height map by a mask to create isolated features.

Port	Description
A (input port)	First input value.
B (input port)	Second input value.

Formula: output = A * B

No parameters.

Filters (Yellow)

Filter nodes perform conditional operations - they test values against conditions and produce different outputs based on the result.

Threshold

Compares a referenced input against a threshold value. If the input passes, it is output with an optional shift applied. If it fails, a fallback constant is output instead.

Port/Parameter	Description
In (input port)	Referenced value to compare against the threshold.
Threshold	Comparison value. Supports height units.
If Greater, Add	Amount added to the input when it is greater than or equal to Threshold. Supports height units.
If Not, Output	Fallback value used when the input is below Threshold. Supports height units.

Formula: if input >= Threshold: output = input + IfGreaterAdd, else output = IfNotOutput

Select

Filters values from a referenced input by a valid range. Values inside the range pass through; values outside are replaced by a constant. Useful for isolating specific elevation bands.

Port/Parameter	Description
In (input port)	Referenced value to test against the range.
Range Min	Lower bound of the accepted range. Supports height units.
Range Max	Upper bound of the accepted range. Supports height units.
Outside Value	Value output when the referenced input falls outside the range. Supports height units.

Formula: if input < RangeMin or input > RangeMax: output = OutsideValue, else output = input

Fill

Replaces values within a given range with a constant. Values outside the range pass through unchanged from the main value flow. This node has two inputs: Value carries the terrain flow, and Ref is tested against the range.

Port/Parameter	Description
Value (input port)	Main incoming value carried through this node. Passes through when Ref is outside the range.
Ref (input port)	Referenced step checked against the range.
Range Min	Lower bound of the fill range. Supports height units.
Range Max	Upper bound of the fill range. Supports height units.
Fill Value	Value written when Ref falls inside the range. Supports height units.

Formula: if Ref >= RangeMin and Ref <= RangeMax: output = FillValue, else output = Value

Test

Checks if a referenced value falls inside a given range. Outputs 1 if inside, 0 if outside. Useful as a boolean mask for further operations.

Port/Parameter	Description
In (input port)	Referenced value to test.
Range Min	Lower bound of the test range. Supports height units.
Range Max	Upper bound of the test range. Supports height units.

Formula: if input >= RangeMin and input <= RangeMax: output = 1, else output = 0

Copy

Copies the value from the connected input. Useful for explicitly branching a signal path or for reusing an earlier result at a different point in the graph.

Port	Description
In (input port)	Step to copy the value from.

Formula: output = input

No parameters.

Beach Mask

A special-purpose node that suppresses beach/shore voxel generation in areas where a mask input exceeds a threshold. The main terrain value (Value port) passes through unchanged - this node only affects whether beaches are allowed at each position.

Port/Parameter	Description
Value (input port)	Main terrain altitude. Passes through unchanged.
Mask (input port)	Mask value used to decide whether beaches are allowed.
Threshold	If Mask is above this normalized value, beach generation is disabled at that position.

Formula: output = Value (pass-through). Side effect: if Mask > Threshold, beaches are suppressed at this world position.

Utilities

Reroute

A small pass-through node displayed as a dot. It forwards the input value to its output without modification. Use reroute nodes to tidy up complex graphs by redirecting connection lines. A single reroute can feed multiple downstream connections.

No parameters. One input, one output.

Example: Basic 3D World

A minimal 3D terrain graph for a world with mountains and caves:

1. Noise 2D (frequency 0.01, octaves 4) - base continental shape
2. Height Gradient (base height 0.3, gradient -2) - solid below 30% height, air above
3. Blend Additive (A=noise, B=gradient) - combine into terrain density
4. Noise 3D (frequency 0.05, octaves 3) - 3D variation for caves
5. Cave Carver (threshold 0.6, strength 1) - hollow out where noise is high
6. Subtract (A=terrain, B=caves) - final density
7. Connect Subtract output to Density terminal

See Also

• Node Reference - Complete list of all available nodes
• Demo7_SmoothTerrain (included in package) - Full 3D terrain graph replicating the classic Earth demo
• Demo 8 - Floating Islands example using 3D density generation