SketcherTools

A non-destructive terrain heightmap authoring plugin for Godot 4, designed to complement brush-based terrain plugins like Terrain3D. Instead of painting terrain directly — which permanently modifies heightmap data — SketcherTools lets you compose terrain elements as independent objects that can be freely repositioned, rescaled, and reconfigured at any time.

The Problem It Solves

Brush-based terrain editing is destructive by nature. Once you sculpt a mountain, you cannot move it — you have to erase and redraw it from scratch. This becomes increasingly painful as your world grows larger.

SketcherTools introduces an object-based composition approach where every terrain formation is a standalone object with its own transform. Nothing is committed to the final heightmap until you explicitly export it.

Key Features

🗺️ Non-Destructive Workflow

Every sketch object stores its configuration as data — position, rotation, scale, noise parameters, blend mode, falloff, and curve modifier. Change anything, anytime. The heightmap is recomputed from scratch every frame during editing.

🏔️ Procedural Heightmap Generation

Three noise algorithms are available as heightmap sources, all implemented natively in GLSL shaders:

• Perlin Noise — smooth, natural-looking terrain base
• Fractal Brownian Motion (FBM) — layered detail with configurable octaves, lacunarity, and gain
• Ridged Noise — sharp mountain ridges and dramatic peaks

🗿 Primitive SDF Shapes

Generate heightmaps from basic geometric forms using Signed Distance Functions:

• Circle — smooth radial gradient, ideal for isolated hills or craters
• Box — square gradient, ideal for plateaus or flat-edged formations

🖼️ External Heightmap Input

Use any existing heightmap image as a sketch object source — real-world elevation data, purchased assets, or heightmaps from other tools.

🎛️ Per-Object Composition Controls

Falloff Smooth the edges of each sketch object to avoid hard cuts:

• None — no falloff applied
• Square — Chebyshev distance-based box falloff
• Radial — Euclidean distance-based circular falloff

Curve Modifier Reshape the height distribution of any sketch object:

• None — use heightmap values as-is
• Exponential — apply power curve to height values
• Free Curve — define a custom curve directly in the Godot editor

Blend Modes (Combine) Control how each object interacts with the terrain below it:

• MAX — take the higher value (additive elevation)
• MIN — take the lower value (depressions, valleys)
• MIX — linear interpolation
• FLATTEN — pull terrain toward a target height
• ADD — direct addition
• SUBTRACT — direct subtraction

Replace Mode Override terrain values directly, with edge transitions controlled entirely by the object's falloff setting.

👁️ Real-Time Preview

• 2D — grayscale heightmap preview updated every frame
• 3D — vertex-displaced plane mesh for topographic preview from any camera angle, with Sobel-based normal recalculation for accurate lighting

📦 Multi-Chunk Canvas

The sketch board uses a GPU-accelerated multi-chunk system powered by MultiMeshInstance3D. Configure canvas size through:

• Chunk Level — number of chunks per axis (1×1 up to 16×16)
• Chunk Size — size of each chunk in meters (64 to 2048)

This allows large terrain canvases without being limited by maximum texture size.

💾 Adaptive Tiling Export

Export your composition as EXR heightmaps (32-bit float, single channel):

• Single file when export size ≥ canvas size
• Multi-tile when export size < canvas size, with coordinate-encoded filenames (e.g. sketcher_128_-256.exr)

Tile filenames encode their world-space position, making them directly compatible with Terrain3D's import system.

🔁 Direct Terrain3D Import

An included import utility reads your exported EXR tiles and places them at the correct world positions in Terrain3D automatically — no manual coordinate entry required.

Workflow Overview