# API reference


**Site index:** [https://modelviewer.2plot.dev/llms.txt](https://modelviewer.2plot.dev/llms.txt) — every page on this site, as Markdown.  
**Network index:** [https://2plot.dev/llms.txt](https://2plot.dev/llms.txt) — The 2plot network; start here to discover sibling sites.  
**Sibling sites:** 13 more in The 2plot network — listed in the site index above.  
**Sitemap:** https://modelviewer.2plot.dev/sitemap.xml  

## dash_model_viewer

### ModelViewer

An interactive 3D model with Augmented Reality support.

| prop | type | default | description |
|---|---|---|---|
| `id` | string \| dict |  | Component id for callbacks. |
| `alt` * | string |  | Accessible description of the model. Required, and not decorative: it is the only thing a screen-reader user gets. |
| `ar` | boolean | True | Enable AR and show the AR affordance where supported. |
| `ar_modes` | string | webxr scene-viewer quick-look | Space-separated AR back-ends, most preferred first. |
| `ar_scale` | 'auto' \| 'fixed' | auto | Whether AR may rescale the model. |
| `ar_status` | string |  | `session-started`, `object-placed`, `failed`, ... |
| `ar_tracking` | string |  | `tracking` or `not-tracking`. |
| `attributes` | dict |  | Raw kebab-case model-viewer attributes.  Read-only props, updated by the component: |
| `camera` | dict |  | `{"orbit", "target", "field_of_view"}`. Only user interaction is reported — programmatic changes are suppressed, or a callback that writes `camera_orbit` would re-trigger itself. |
| `camera_change_debounce` | number | 100 | Milliseconds to coalesce `camera-change` events before updating `camera`. **Do not set this to 0 casually** — the event fires at frame rate, so 0 means a callback per frame per viewer. |
| `camera_controls` | boolean | True | Let the user orbit, zoom and pan. |
| `camera_orbit` | string |  | `"theta phi radius"`, e.g. `"45deg 70deg 2.5m"`. Two-way: also reported back through `camera`. |
| `camera_target` | string |  | `"X Y Z"` in metres, e.g. `"0m 1m 0m"`. |
| `children` | list of components |  | `Slot` components. Hotspots, a custom AR button, a poster, a progress bar — every one of those is a named slot. |
| `class_name` | string |  | CSS class for the viewer element. |
| `field_of_view` | string |  | e.g. `"30deg"`.  - min_field_of_view / max_field_of_view (string; optional): Zoom limits.  - min_camera_orbit / max_camera_orbit (string; optional): Orbit limits, `"auto auto auto"` for none. |
| `interpolation_decay` | number |  | Camera transition speed. Lower is slower; `0` is instant. This is what makes a programmatic camera move read as a flight rather than a jump-cut. |
| `max_camera_orbit` | Optional[str] |  |  |
| `max_field_of_view` | Optional[str] |  |  |
| `min_camera_orbit` | Optional[str] |  |  |
| `min_field_of_view` | Optional[str] |  |  |
| `model_info` | dict |  | `{"dimensions": {"x","y","z"}, "variants": [...], "animations": [...]}`, set on load. Dimensions are in metres — this is the prop that removes the bounding-box maths from user JS. |
| `model_state` | dict |  | `{"status": "loading" \| "loaded" \| "error", "progress": float}`. |
| `pick_on_click` | boolean | False | When True, clicking the model reports the 3D surface point under the cursor through `scene_point`. |
| `poster` | string |  | Image shown until the model is ready. |
| `scene_point` | dict |  | `{"position", "normal", "uv"}` for the last picked point, when `pick_on_click` is set. |
| `shadow_intensity` | number |  | 0 to 1. |
| `src` * | string |  | URL of the `.glb` / `.gltf` model. |
| `style` | dict |  | CSS for the viewer element. It has no intrinsic size — give it one. |
| `tone_mapping` | string | neutral | `neutral`, `aces`, `agx`, `commerce`, ... |
| `touch_action` | 'pan-y' \| 'pan-x' \| 'none' | pan-y | Which touch gestures the page keeps rather than the model. |
| `variant_name` | string |  | GLTF material variant. `None` (or `"default"`) selects the model's default. |

### Slot

A named slot inside a :class:`ModelViewer`.

| prop | type | default | description |
|---|---|---|---|
| `id` | string \| dict |  | Component id for callbacks. |
| `children` | list of components |  | Slot content. Any Dash component. |
| `class_name` | string |  | Added alongside the built-in `dmv-slot` class. |
| `n_clicks` | number | 0 | Increments on click. Use as a callback `Input` — this is how a hotspot drives a camera move without any clientside JavaScript. |
| `normal` | string |  | `"X Y Z"` surface normal; controls hotspot occlusion behaviour. |
| `position` | string |  | `"X Y Z"` in model space. Required for hotspots. |
| `slot` * | string |  | The slot name, e.g. `"hotspot-1"`, `"ar-button"`, `"poster"`. |
| `style` | dict |  | CSS for the slot element. |