AndreyStartsev · Nov 11, 2026
diff --git a/README.md b/README.md
@@ -9,6 +9,8 @@ RvtIO is a .NET library and command line tool that reads Autodesk Revit projects
 - Reads elements, parameters, geometry, file metadata and project information.
 - Queries elements through `FilteredElementCollector`.
 - Exports IFC2X3 coordination view, with optional Revit parameters as property sets.
+- Exports browser-ready 3D scenes as binary glTF 2.0 (`.glb`) or versioned `rvtio-scene/1` JSON with reusable meshes, instancing, materials and element metadata.
+- Exports a single-file offline 3D HTML viewer (`.html`) with an embedded WebGL inspection app and zero external network dependencies.
 - Writes compact JSON or a full JSON dump with every parameter and geometry.
 
 ## Install
@@ -57,7 +59,15 @@ Export IFC with Revit parameters as property sets:
 rvtio project.rvt project.parameters.ifc --ifc-revit-parameters
 ```
 
-A `.ifc` output path selects IFC. Any other output path selects JSON, which is compact by default. If the output path is omitted, the tool writes `output.json`. Diagnostics go to standard error.
+Export a binary glTF 2.0 scene or a self-contained offline 3D HTML viewer:
+
+```sh
+rvtio project.rvt project.glb
+rvtio project.rvt project.html --viewer-title "Project Review"
+rvtio project.rvt project.scene.json
+```
+
+A `.ifc` output path selects IFC, `.glb` selects glTF 2.0, `.html`/`.htm` selects the standalone 3D HTML viewer, `.scene.json` (or `--scene-json`) selects the `rvtio-scene/1` JSON contract, and any other output path selects data JSON, which is compact by default. If the output path is omitted, the tool writes `output.json`. Diagnostics go to standard error. See [3D scene export and standalone HTML viewer](docs/scene-export.md) for the scene contract and viewer options.
 
 Export the state of one project phase:
 

diff --git a/docs/export-report.md b/docs/export-report.md
@@ -72,7 +72,7 @@ The report is one JSON object, UTF-8, property names in camelCase. `schema` name
 | `elements.inTable`, `elements.decoded` | Rows of the element table, and those with a parsed record. `decodedFraction` is their quotient (1 for an empty table). |
 | `issues[]` | Other findings that make a read `partial`, as `stream`, `code`, `detail`. The one code is `no-rows`: the element table decoded no row (a project always has elements, so the table did not decode). |
 | `elements.undecoded[]` | Rows of the element table without a parsed record, as `class`, `reason`, `count`, `examples`. The class of an element that never decoded is `unknown`. |
-| `export.format` | `ifc`, `json` (the compact export) or `json-full`. |
+| `export.format` | `ifc`, `glb`, `html`, `scene-json`, `json` (the compact export) or `json-full`. |
 | `export.considered`, `exported`, `skipped` | Parsed elements the export looked at, wrote, and left out, counted as the exporter counts them (`exported` counts elements, not product entities: for example, a roof element that writes two product entities, an `IfcRoof` and an `IfcSlab` with the same tag, counts once in `exported`, so the exported total can be below the number of product entities). `exportedFraction` is `exported / considered`. |
 | `export.skippedByClass[]` | Every skipped element class with its reason, count and up to five element ids (`examples`), largest first. The counts add up to `export.skipped`. |
 
@@ -88,6 +88,10 @@ A level, a room and the topography that is written as the site are listed as ski
 
 The compact export writes the rows of the element table: `block-only-record` and `record-outside-exact-element-table` are the two reasons an element is left out. The full dump (`--json-full`) writes every parsed element.
 
+### Reasons of a scene or HTML viewer export
+
+`block-only-record`, `group-template`, `record-outside-exact-element-table`, `owned-by-family-nonspatial`, `type-element`, `non-physical-category`, `no-project-phase-reference`, `outside-export-phase`, `filtered-out`, `filtered-by-element-id`, `filtered-by-category`, `filtered-by-predicate`, `no-geometry`.
+
 ## Scripting
 
 ```

diff --git a/docs/getting-started.md b/docs/getting-started.md
@@ -11,15 +11,17 @@ dotnet tool install --global RvtIO.Cli
 rvtio project.rvt project.ifc
 ```
 
-A `.ifc` output path selects IFC. Any other output path selects JSON, which is compact by default.
+A `.ifc` output path selects IFC, `.glb` selects a binary glTF 2.0 scene, `.html` / `.htm` selects a standalone 3D HTML viewer, and `.scene.json` (or `--scene-json`) selects the versioned `rvtio-scene/1` JSON contract. Any other output path selects data JSON, which is compact by default.
 
 ```sh
+rvtio project.rvt project.glb
+rvtio project.rvt viewer.html
 rvtio project.rvt project.compact.json --compact-json
 rvtio project.rvt project.full.json --json-full
 rvtio project.rvt project.parameters.ifc --ifc-revit-parameters
 ```
 
-Run `rvtio --help` for all options. The exit codes and the `--report` file are described in [Export report and exit codes](export-report.md).
+Run `rvtio --help` for all options. Scene and viewer options are described in [Scene and HTML 3D viewer export](scene-export.md); the exit codes and the `--report` file are described in [Export report and exit codes](export-report.md).
 
 ## Library
 

diff --git a/docs/index.md b/docs/index.md
@@ -9,6 +9,7 @@ RvtIO is a .NET library and command line tool that reads Autodesk Revit projects
 - Reads elements, parameters, geometry, file metadata and project information.
 - Queries elements through `FilteredElementCollector`.
 - Exports IFC2X3 coordination view, with optional Revit parameters as property sets.
+- Exports browser-ready 3D scenes as binary glTF 2.0 (`.glb`), versioned `rvtio-scene/1` JSON, or a self-contained offline 3D HTML viewer (`.html`).
 - Writes compact JSON or a full JSON dump with every parameter and geometry.
 
 The library targets .NET 8 and .NET 10, uses managed code only, and supports Windows, Linux and macOS.
@@ -17,6 +18,7 @@ The library targets .NET 8 and .NET 10, uses managed code only, and supports Win
 
 - [Getting started](getting-started.md): install the tool or the package and run a first export.
 - [Public API](public-api.md): the supported surface of the library.
+- [Scene and HTML 3D viewer export](scene-export.md): `.glb`, `rvtio-scene/1` JSON and standalone `.html` 3D viewer options.
 - [Export report and exit codes](export-report.md): how a complete export is told from a partial one.
 - [API reference](api/RvtIO.yml): every public type, generated from the XML documentation.
 - [Source on GitHub](https://github.com/IOExtend/RvtIO) and [DeepWiki](https://deepwiki.com/IOExtend/RvtIO) for an automatically generated overview of the repository.

diff --git a/docs/public-api.md b/docs/public-api.md
@@ -41,12 +41,16 @@ extension and label helpers carry the ids and names stored in the file format.
 | `IfcUnitFamily` | The length unit family an export of the current profile declares, by the length format of the project: `Metre` for metres and for metres and centimetres, `Foot` for feet, feet and fractional inches and US survey feet, `Millimetre` for millimetres, for every other format and for an unreadable one. The legacy profile always declares millimetres. |
 | `CompactJsonExporter` | `Export(rvtPath, outputPath, readerOptions, options)` reads a file and writes the compact JSON. |
 | `CompactJsonExportOptions` | `JsonClassNamePrefix`: text put in front of every class name in the `name` field. |
+| `SceneExporter` | Builds a `ModelScene` (`Build`, `OpenAndBuild`), writes and reads the versioned `rvtio-scene/1` JSON (`ExportJson`, `LoadJson`), and writes binary glTF 2.0 `.glb` (`ExportGlb`); see [3D scene export](scene-export.md). |
+| `HtmlViewerExporter` | Writes a single-file offline 3D HTML viewer (`Export`, `ExportToString`) embedding a `ModelScene` and WebGL viewer. |
+| `SceneExportOptions`, `HtmlViewerOptions` | Filtering (`ElementIds`, `CategoryIds`, `ElementFilter`), metadata (`IncludeParameters`, `IncludeTypeParameters`, `IncludedParameterNames`, `MaxParametersPerElement`), coordinate (`ApplySharedCoordinates`, `IncludeGrids`, `IncludeRooms`), viewer (`Title`, `InitialTheme`, `ShowGridsByDefault`) and diagnostic (`SkipLog`, `DiagnosticOutput`) options. |
+| `ModelScene` and scene records | `ModelScene`, `SceneMaterial`, `SceneMeshPrototype`, `SceneMeshInstance`, `SceneElement`, `ScenePropertyGroup`, `SceneProperty`, `SceneCategoryNode`, `SceneGridLine`, `SceneCompletenessSummary`, `SceneOmittedGroup` (`RvtIO.Scene`). |
 
 ## Diagnostics
 
 The library never writes to the console. A diagnostic message is written only when the caller gives a `TextWriter`:
 `RvtReaderOptions.DiagnosticOutput` for a read (and for `CompactJsonExporter.Export`), `IfcExporter.DiagnosticOutput` (or the
-constructor argument) for an IFC export. The default is `null`, which is silent. The writer is scoped to the call that
+constructor argument) for an IFC export, `SceneExportOptions.DiagnosticOutput` for a scene or HTML viewer export. The default is `null`, which is silent. The writer is scoped to the call that
 received it, so concurrent calls with different writers do not mix.
 
 The `rvtio` command line tool sets the writer to standard error.
diff --git a/docs/scene-export.md b/docs/scene-export.md
@@ -0,0 +1,126 @@
+---
+title: Scene and HTML 3D viewer export
+---
+
+# 3D scene export and standalone HTML viewer
+
+`RvtIO` exports browser-ready 3D geometry and element metadata directly from `.rvt` projects and `.rfa` families in three forms:
+
+1. **Binary glTF 2.0 (`.glb`)** — standard 3D asset with reusable meshes, per-instance transforms, PBR materials and element metadata in `node.extras`.
+2. **Versioned scene JSON (`rvtio-scene/1`)** — compact JSON contract with Base64 typed-array mesh buffers, category hierarchy, grouped element properties, datum grids and completeness notes.
+3. **Self-contained 3D HTML viewer (`.html`)** — single offline HTML file embedding the `rvtio-scene/1` payload and a zero-dependency WebGL viewer with no external network requests or CDN links.
+
+## Command line
+
+Export a binary glTF 2.0 scene:
+
+```sh
+rvtio project.rvt project.glb
+```
+
+Export a self-contained HTML viewer:
+
+```sh
+rvtio project.rvt project.html --viewer-title "Tower A - Architectural"
+```
+
+Export the `rvtio-scene/1` JSON contract:
+
+```sh
+rvtio project.rvt project.scene.json
+rvtio project.rvt scene.json --scene-json --scene-pretty
+```
+
+Filter by category or element IDs, control exported metadata, or apply shared coordinates:
+
+```sh
+rvtio project.rvt envelope.html --scene-categories Walls,Windows,Doors,Roofs
+rvtio project.rvt subset.glb --scene-ids 184201,184205 --scene-no-parameters
+rvtio project.rvt site.glb --scene-shared-coordinates --scene-include-rooms
+```
+
+### Options
+
+| Option | Effect |
+| --- | --- |
+| `--scene-json` | Write `rvtio-scene/1` JSON instead of the compact data JSON. Automatic when the output path ends with `.scene.json`. |
+| `--scene-pretty` | Indent the `rvtio-scene/1` JSON output. |
+| `--scene-categories <c1,c2,...>` | Include only the listed categories. Accepts numeric category IDs (`-2000011`), `BuiltInCategory` names (`OST_Walls`) or English category names (`Walls`). |
+| `--scene-ids <id1,id2,...>` | Include only the listed Revit element IDs. |
+| `--scene-no-parameters` | Omit element and type parameters from the scene and HTML viewer. |
+| `--scene-parameter-names <p1,...>` | Include only parameters matching the listed names or captions. |
+| `--scene-shared-coordinates` | Transform coordinates by `RevitFileInfo.SharedTransform` before computing the relative-to-center (`rtcOffset`) origin. |
+| `--scene-include-rooms` | Export room volumes (`OST_Rooms`) as translucent 3D enclosures. |
+| `--scene-no-grids` | Omit datum grid lines (`OST_Grids`). |
+| `--glb-z-up` | Keep Revit right-handed Z-up coordinates in `.glb` instead of rotating the root node to glTF Y-up. |
+| `--viewer-title <text>` | Set a custom document and header title in the HTML viewer. |
+| `--viewer-theme <dark\|light>` | Set the initial color theme of the HTML viewer (default: `dark`). |
+
+All scene exports participate in `--report <report.json>` (`export.format` is `glb`, `html` or `scene-json`) and respect `--raise-limits` and `--allow-partial`.
+
+## Library API
+
+```csharp
+using RvtIO;
+using RvtIO.BuiltIns;
+using RvtIO.Scene;
+
+var doc = RvtDocument.Open("project.rvt", new RvtReaderOptions
+{
+    R22Layout = true,
+    SeparateFacesWithDistinctOpenings = true,
+    SystemFamilyNameLocale = "ENU",
+});
+
+var options = new HtmlViewerOptions
+{
+    Title = "Project Review",
+    InitialTheme = "dark",
+    CategoryIds = new HashSet<int>
+    {
+        (int)BuiltInCategory.OST_Walls,
+        (int)BuiltInCategory.OST_Doors,
+        (int)BuiltInCategory.OST_Windows,
+    },
+};
+
+ModelScene scene = SceneExporter.Build(doc, options);
+SceneExporter.ExportGlb(scene, "project.glb");
+SceneExporter.ExportJson(scene, "project.scene.json", indented: true);
+HtmlViewerExporter.Export(scene, "project.html", options);
+```
+
+`SceneExporter.OpenAndBuild(rvtPath, options)` and `HtmlViewerExporter.Export(rvtPath, outputPath, options)` open the file with 3D geometry decoding (`R22Layout = true`) enabled by default.
+
+## `rvtio-scene/1` JSON contract
+
+The scene JSON is a single UTF-8 object with `camelCase` property names and `"schema": "rvtio-scene/1"`. Additive properties may be introduced within `rvtio-scene/1`; breaking changes increment the schema version.
+
+| Property | Meaning |
+| --- | --- |
+| `schema` | Always `"rvtio-scene/1"`. |
+| `title` | Human-readable model title. |
+| `units` | `"m"` (metres). |
+| `coordinateSystem` | `"right-handed-z-up"`. |
+| `rtcOffset` | `[x, y, z]` double-precision origin offset in metres. Add `rtcOffset` to any scene coordinate to recover world metres: $P_{\text{world}} = P_{\text{scene}} + \text{rtcOffset}$. |
+| `sharedTransform` | Optional 12-double `[basisX(3), basisY(3), basisZ(3), originMetres(3)]` internal-to-shared transform when present in the file. |
+| `boundsMin`, `boundsMax` | `[x, y, z]` bounding box of the scene in RTC metres. |
+| `materials[]` | `{ index, revitMaterialId?, name, color: [r,g,b], opacity, metallic, roughness, doubleSided }`. |
+| `meshes[]` | Reusable indexed triangle prototypes: `{ index, sourceSymbolId?, isMirroredVariant, vertexCount, triangleCount, indexType ("uint16"\|"uint32"), localBoundsMin, localBoundsMax, positionsB64, normalsB64, indicesB64 }`. `positionsB64` and `normalsB64` are little-endian IEEE 754 `Float32Array` bytes (`vertexCount * 3` floats); `indicesB64` is little-endian `Uint16Array` or `Uint32Array` (`triangleCount * 3` indices). |
+| `instances[]` | Placed mesh occurrences: `{ meshIndex, elementIndex, elementId, materialIndex, matrix, boundsMin, boundsMax }`, where `matrix` is a 16-float column-major 4x4 affine matrix in RTC metres. |
+| `elements[]` | Exported physical elements: `{ id, uniqueId?, name, category, categoryId?, familyName?, typeName?, level?, hostId?, isInstanced, instanceIndices, propertyGroups: [{ group, properties: [{ name, value }] }] }`. |
+| `categories[]` | Category tree nodes: `{ category, categoryId?, elementIndices }`. |
+| `grids[]` | Datum grid segments in RTC metres: `{ id, name, start: [x,y,z], end: [x,y,z] }`. |
+| `completeness` | `{ totalElements, consideredElements, exportedElements, instancedElements, reusableMeshCount, instanceCount, vertexCount, triangleCount, isPartialGeometry, notes[], omittedGroups: [{ code, reason, count }] }`. |
+
+### Precision and instancing guarantees
+
+- **Relative-to-center (RTC) coordinates**: Models located more than 100 m from the origin (such as georeferenced shared coordinates) automatically shift their scene origin to the double-precision bounding-box center stored in `rtcOffset`, preventing 32-bit `Float32` vertex jitter in WebGL and glTF viewers.
+- **Reusable family symbol meshes**: Repeated `FamilyInstance` placements share a single `SceneMeshPrototype` in `meshes[]` (and a single glTF `mesh` in `.glb`) placed by per-instance 4x4 transforms.
+- **Mirrored instances**: Instances whose placement transform has negative determinant ($\det(M) < 0$) reference a dedicated mirrored prototype variant (`isMirroredVariant: true`) with reversed triangle index winding `(i0, i2, i1)` so counter-clockwise front faces and outward `(M^{-1})^T` normals are preserved in standard glTF 2.0 and WebGL pipelines.
+
+## Standalone HTML viewer capabilities and security
+
+- **Navigation**: Orbit (left-drag), pan (right-drag or Shift + drag), cursor-targeted zoom (wheel), fit-to-model / fit-to-selection (`F`), orthographic/perspective toggle (`O`), and an interactive 3D ViewCube (`Top`, `Bottom`, `Front`, `Back`, `Left`, `Right`, `Home`).
+- **Inspection & filtering**: 3D raycast picking with selection highlight, category hierarchy browser with visibility toggles, live text search across element names/IDs/categories/types/levels, `Hide` (`H`), `Isolate` (`I`), `Show All` (`Esc` / button), grouped property inspector, 6-axis interactive section box, datum grid toggle (`G`), 3D point-to-point distance measurement (`M`), theme toggle, and a model completeness summary dialog.
+- **Offline & XSS safety**: Zero external scripts, stylesheets, fonts or images are referenced. All embedded JSON escapes `<`, `>`, `&` (`\u003C`, `\u003E`, `\u0026`) so `</script>` payloads in untrusted model strings cannot break out of `<script type="application/json">`, `<title>` is HTML-encoded, and the viewer UI renders every model string exclusively via DOM `.textContent`.
diff --git a/docs/toc.yml b/docs/toc.yml
@@ -5,6 +5,8 @@
   items:
     - name: Public API
       href: public-api.md
+    - name: Scene and HTML 3D viewer export
+      href: scene-export.md
     - name: Export report and exit codes
       href: export-report.md
     - name: Coverage report