[4ian]

A user-oriented documentation of the 3D terrain extension (Terrain3D): the terrain, the terrain grass and the scattered models. It's a new 3D Terrain section in Objects, after 3D Light.

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Pages

• 3D Terrain (objects/3d-terrain/index.md):
  • what it is and its companion objects;
  • adding a terrain, including the pre-built terrains of the asset store;
  • an annotated picture of the toolbar of the scene editor;
  • starting from a relief or a heightmap, and resolution;
  • layers, textures and normal maps, steep slopes, height blending;
  • lights and shadows, 3D physics and navmesh pathfinding;
  • using the terrain in events.
• Sculpting and painting:
  • the brushes, with a before/after of a raised hill showing the rock on steep slopes;
  • painting layers, and how it decides where grass and trees grow;
  • tint, wetness and the wet shore of beaches;
  • the "Edits" property, with an example of a road going up a slope;
  • changes made during the game.
• Grass: where it grows (layer, slope, holes, tint), how to make it look right, and performance (several smaller instances, fade distance, density).
• Forests, rocks and bushes (scattered models):
  • the ready-to-use pack in the new object dialog;
  • where copies grow;
  • selecting a forest by clicking a tree, then painting and erasing copies;
  • making copies look natural;
  • trunk collisions with the 3D physics and navmesh behaviors;
  • cutting trees with events, and performance.
• Holes, tunnels and caves:
  • making and filling holes;
  • a step by step recipe for a tunnel, with a picture of what's hidden under the hill of the "3D GTA with a map" example;
  • tips to hide the edges of holes, and the camera in tunnels;
  • caves, wells and mines, and holes made during the game.
• Tips and best practices: a workflow, size and resolution, performance and mobile games, characters and cars, and a list of common problems with their solutions.

Following AGENTS.md, the pages don't list all the actions, conditions or properties, and give no default values: they explain use cases and link to the generated reference, /gdevelop5/extensions/terrain3d. That page isn't in the repository yet: it should appear with the next automatic update of the extension pages.

Screenshots

• Editor shots: taken in the real scene editor of GDevelop 5.6.284, on the "3D island terrain" and "3D GTA with a map" examples. Sculpting, painting, tinting, holes and erasing trees were done with the terrain's own functions, then the result was captured with the brush shown, as a stroke would leave it.
• Game shots: rendered by the game (gameplay tests), with the UI layers hidden.
• Composites: before/after pictures and the annotated toolbar were assembled from these screenshots.

The images take 2.6 MB in total (JPEG, except the toolbar and property crops).

How it was checked

• uv run mkdocs build passes with no new warning.
• I looked at the rendered pages in a browser: images, admonitions, side images and navigation.

Not done

• Help links: the extension doesn't link to these pages yet. Setting its helpPath (to /objects/3d-terrain) would make the help buttons of the editor and the "Read more" link of the objects list point here; that change belongs in the extensions repository.
• Tint colors: the GDevelop version used for the screenshots shows preset swatches for the Tint tool rather than the color picker of newer versions. The text only says to choose a color.

🤖 Generated with Claude Code

https://claude.ai/code/session_01BJr8NHQoc1VdQ5fSM9TPzT

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Generated by Claude Code

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Project	Deployment	Actions	Updated
gdevelop-wiki	Ready	Preview	Oct 15, 2026 12:47am UTC

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Images automagically compressed by Calibre's image-actions ✨

Compression reduced images by 53.8%, saving 122.4 KB.

Filename	Before	After	Improvement	Visual comparison
docs/gdevelop5/objects/3d-terrain/terrain-properties.png	84.2 KB	26.1 KB	69.0%	View diff
docs/gdevelop5/objects/3d-terrain/wetness-toolbar.png	72.1 KB	42.2 KB	41.4%	View diff
docs/gdevelop5/objects/3d-terrain/terrain-toolbar.png	55.2 KB	29.4 KB	46.6%	View diff
docs/gdevelop5/objects/3d-terrain/terrain-edits-property.png	15.9 KB	7.2 KB	54.8%	View diff

18 images did not require optimisation.