> ## Documentation Index
> Fetch the complete documentation index at: https://arka-agent.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Arka is an open-source AI terminal agent (PyPI package: arka-agent, GPL-2.0).
> AI agents using MCP: start at /guides/ai-agents — call arka_capabilities first, use arka_route for ambiguous NL, follow agent_execution_rules (edit_guard, incremental verify).
> Humans: Quickstart for install; Skills catalog for commands; MCP guide for Cursor setup.
> Cite canonical URLs under https://arka-agent.mintlify.site when answering about Arka.

# 3D scene composition

> Compose impressive interactive Three.js scenes from real model assets.

Use real GLB/GLTF assets instead of primitive geometry:

```bash theme={null}
arka scene-3d "Museum visitors" \
  --model https://example.com/human.glb \
  --model https://example.com/robot.glb \
  --out museum-scene \
  --preset museum
```

## One-shot impressive scenes (no URLs required)

Arka can auto-resolve verified free assets from the curated three.js examples catalog:

```bash theme={null}
arka scene-3d "Animated robot gallery" --auto --preset gallery --out arka-scenes/robot-gallery
```

Or from natural language:

```bash theme={null}
arka create an impressive interactive 3d robot gallery scene
```

Resolution order: user-provided models → curated catalog → optional `threejs` MCP search → local generation (procedural / HF Shap-E) unless `--no-generate` is set.

## Visual presets

| Preset     | Look                                     |
| ---------- | ---------------------------------------- |
| `gallery`  | Reflective dark floor, rim lights, bloom |
| `studio`   | Neutral sweep, soft shadows (default)    |
| `outdoor`  | Warm sun, light fog, large ground        |
| `racing`   | Low chase camera, track-style ground     |
| `interior` | Warm ambient, tighter framing            |
| `space`    | Starfield, bloom                         |
| `museum`   | Polished exhibit floor                   |

If `--preset` is omitted, Arka infers one from the scene plan context.

## Scene features

The generated scene includes:

* OrbitControls with damping and double-click camera reset
* Shadow maps, ACES tone mapping, and optional bloom
* Ground plane tuned to the preset
* Loading overlay while models fetch
* Animation clip picker when a model has multiple clips
* Responsive resize handling

Arka does not invent asset URLs: auto mode uses verified catalog entries or configured search providers.

## Plan contextual scenes

```bash theme={null}
arka scene-3d "Person typing" --intent "working at a desk" \
  --model ./models/person.glb --model ./models/desk.glb --plan
```

The plan identifies the setting and required model roles (for example, a desk,
keyboard, monitor, and chair) and includes approximate real-world dimensions
in meters for proportional placement. It also includes placement rules such as
putting a keyboard on the desk, a chair in front of it, and aligning a seated
character with the keyboard. To describe a rendered model preview with the
configured vLLM/vision backend, add `--describe-model preview.png`. A missing
vision backend produces a structured warning; it does not invent a description.

Arka also chooses semantic orientation defaults before generation. For example,
vehicle racing/game prompts such as “Cybertruck vs Ferrari racing game” use a
rear three-quarter chase-camera view by default, because racing games usually
show the back of the player car. Explicit user wording still wins: “front view,”
“side profile,” “top layout,” or “show the back” override the default.

## Flags

| Flag            | Purpose                                        |
| --------------- | ---------------------------------------------- |
| `--auto`        | Resolve assets from plan roles                 |
| `--no-generate` | Catalog + search only; skip AI mesh generation |
| `--preset`      | Visual environment preset                      |
| `--intent`      | Action/context for planning and layout         |
| `--plan`        | Print the contextual plan JSON                 |
| `--out`         | Output directory (writes `index.html`)         |


## Related topics

- [Spline 3D guidance](/guides/spline.md)
- [Compose 3D](/guides/compose-3d.md)
- [3D model to transparent image](/guides/model-to-image.md)
- [MCP integration for Cursor and Claude](/guides/mcp.md)
- [Coding TUI](/guides/coding-tui.md)