Scenes & Entities

Structure

The Entity Model

A scene is a hierarchy of entities. An entity is a lightweight identity — a name, a parent and children — that gains behaviour by holding components. Systems iterate the components each frame: the render extractor collects meshes and lights, the physics world steps rigid bodies, the animation systems pose skeletons.

You create entities in the World Outliner and attach components in the Details panel. Transforms are hierarchical — moving a parent moves its children.

Reference

Component Reference

Every component in the engine, grouped by area, with its user-facing properties as they appear in the Details panel.

Transforms & rendering

Physics

Animation

Audio, scripts & gameplay

In-world UI

Entities can carry canvas-based UI components — UI Canvas (screen-space or world-space), UI Element (anchored rect), UI Text, UI Image and UI Button. For menus and HUDs, prefer the standalone UI Widget system.

Special entities

Sky & Weather Entities

The sky and the weather are ordinary, deletable scene entities — Sky carries the Environment component (the entire procedural sky) and owns the Sun and Moon lights as children; Weather carries the Weather component and drives cloud cover, fog, wind and precipitation into the Environment. Add and remove them via View ▸ Environment; a scene without a Sky renders a flat background and skips the whole sky pass.

Game and Simulation project templates seed both into the startup scene. All settings are documented under Rendering ▸ Sky & Atmosphere.

World building

Terrain

A terrain is an entity with a Terrain component — a heightfield created and sculpted in the editor's Landscape mode (size, resolution, height scale, optional procedural seed noise; then Raise / Lower / Smooth / Flatten / Ramp / Roughen brushes).

Under the hood the terrain builds a grid of chunk child entities, each with its own mesh and automatic LOD chain, so the standard frustum culler and LOD system handle distant terrain cheaply. Skirt geometry hides seams between LOD levels, and sculpt strokes regenerate only the chunks they touch. The terrain uses a single material (assign your own via its Material component).

Vegetation

Foliage

The Foliage component scatters mesh instances procedurally across the terrain on the same entity — Density, Seed, Min/Max Scale and a Draw Distance, with a Regenerate button. Instances render through GPU instancing with per-instance tinting, so thousands of blades or bushes cost a handful of draw calls.

Reuse

Prefabs

Right-click any entity in the Outliner and choose Save as Prefab — the entity and all its descendants are captured into a prefab asset (internally the same compact binary format as a scene, limited to the subtree). Dragging the prefab back into a scene instantiates a fresh copy with fresh entity ids, reparented wherever you drop it.

On disk

Scene Files

In the editor, scenes are versioned, human-readable JSON saved as .hescene. Every entity records its hierarchy and a component map; asset references (meshes, materials, scripts …) are stored as UUIDs so they survive file moves:

{
  "version": "1.1",
  "entities": [
    {
      "id": 1,
      "name": "Cube",
      "parent": 0,
      "children": [],
      "components": {
        "transform": {
          "position": [0, 1, 0],
          "rotation": [0, 0, 0],
          "scale":    [1, 1, 1]
        },
        "mesh":     { "asset": "9f2c…", "castsShadow": true },
        "material": { "asset": "b41a…" }
      }
    }
  ]
}

Exported games ship scenes in a compact binary (CBOR) form packed into the .hpak archive. The Level Script graph is stored inside the scene file, so scene and logic travel together.

Big worlds

Additive Loading & Zones

Beyond loading one scene at a time, the engine supports additive loading: merging another scene into the running world as a zone. In the editor, File ▸ Add Scene Additive… merges a scene for editing. At runtime, the scene scripting group drives seamless transitions and streaming:

• scene.load — switches scenes, swapping the world only after the new one finished building (no half-loaded frame).
• scene.loadAdditive — streams a zone in at a position, optionally hidden for a later instant reveal.
• scene.showZone / hideZone / setZonePosition / unloadZone — manage streamed zones by id.

The same calls are available to Lua, Python and HorizonCode — see the node reference for the full list.