CesiumGS · ggetz · Aug 27, 2025 · Aug 26, 2025 · Aug 26, 2025 · Aug 26, 2025
diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
diff --git a/Apps/Sandcastle/gallery/3D Tiles Gaussian Splatting Comparison.html b/Apps/Sandcastle/gallery/3D Tiles Gaussian Splatting Comparison.html
@@ -74,7 +74,7 @@
         });
 
         try {
-          const left = await Cesium.Cesium3DTileset.fromIonAssetId(3591160);
+          const left = await Cesium.Cesium3DTileset.fromIonAssetId(3667784);
           viewer.scene.primitives.add(left);
           left.splitDirection = Cesium.SplitDirection.LEFT;
 

diff --git a/Apps/Sandcastle/gallery/3D Tiles Gaussian Splatting.html b/Apps/Sandcastle/gallery/3D Tiles Gaussian Splatting.html
@@ -36,7 +36,7 @@
         const viewer = new Cesium.Viewer("cesiumContainer");
 
         try {
-          const tileset = await Cesium.Cesium3DTileset.fromIonAssetId(3591124);
+          const tileset = await Cesium.Cesium3DTileset.fromIonAssetId(3667783);
           viewer.scene.primitives.add(tileset);
           viewer.zoomTo(
             tileset,

diff --git a/CHANGES.md b/CHANGES.md
@@ -12,14 +12,15 @@
 #### Fixes :wrench:
 
 - Removes the minimum tile threshold of four for WMTS. [#4372](https://github.com/CesiumGS/cesium/issues/4372)
+- Fixed a crash that could happen when loading PNTS (point cloud) data that contained a batch table without a binary part [#11166](https://github.com/CesiumGS/cesium/issues/11166)
 
 #### Additions :tada:
 
 - Added support for the [EXT_mesh_primitive_restart](https://github.com/KhronosGroup/glTF/pull/2478) glTF extension. [#12764](https://github.com/CesiumGS/cesium/issues/12764)
 
-#### Fixes :wrench:
+#### Deprecated :hourglass_flowing_sand:
 
-- Fixed a crash that could happen when loading PNTS (point cloud) data that contained a batch table without a binary part [#11166](https://github.com/CesiumGS/cesium/issues/11166)
+- Deprecated support of the `KHR_spz_gaussian_splats_compression` extension in favor of the latest 3D Gaussian Splatting extensions for glTF, `KHR_gaussian_splatting` and `KHR_gaussian_splatting_compression_spz_2`. The deprecated extension will be removed in version 1.135. Please retile your existing 3D Tiles using Gaussian splatting before that time. [#12837](https://github.com/CesiumGS/cesium/issues/12837)
 
 ## 1.132 - 2025-08-01
 
@@ -2475,6 +2476,7 @@ _This is an npm-only release to fix a publishing issue_.
     tileset.boundingSphere.center,
   );
   ```
+
   - This also fixes several issues with clipping planes not using the correct transform for tilesets with children.
 
 ### Additions :tada:
@@ -4320,6 +4322,7 @@ _This is an npm-only release to fix a publishing issue_.
                 isStopIncluded : true,
                 data : data
             });
+
     - `TimeInterval.fromIso8601` now takes a single options parameter. Code that looked like:
 
             TimeInterval.fromIso8601(intervalString, true, true, data);
@@ -4332,6 +4335,7 @@ _This is an npm-only release to fix a publishing issue_.
                 isStopIncluded : true,
                 data : data
             });
+
     - `interval.intersect(otherInterval)` -> `TimeInterval.intersect(interval, otherInterval)`
     - `interval.contains(date)` -> `TimeInterval.contains(interval, date)`
 

diff --git a/Specs/Data/Cesium3DTiles/GaussianSplats/tower/0/0.glb b/Specs/Data/Cesium3DTiles/GaussianSplats/tower/0/0.glb
diff --git a/Specs/Data/Cesium3DTiles/GaussianSplats/tower/tileset.json b/Specs/Data/Cesium3DTiles/GaussianSplats/tower/tileset.json
@@ -1,66 +1,68 @@
 {
-    "asset": {
-        "extras": {
-            "ion": {
-                "georeferenced": true,
-                "movable": true
-            }
-        },
-        "version": "1.1"
+  "asset": {
+    "extras": {
+      "ion": {
+        "georeferenced": true,
+        "movable": true
+      }
     },
-    "extensions": {
-        "3DTILES_content_gltf": {
-            "extensionsRequired": [
-                "KHR_spz_gaussian_splats_compression"
-            ],
-            "extensionsUsed": [
-                "KHR_spz_gaussian_splats_compression"
-            ]
-        }
-    },
-    "extensionsUsed": [
-        "3DTILES_content_gltf"
-    ],
-    "geometricError": 14.76778488662848,
-    "root": {
-        "boundingVolume": {
-            "box": [
-                1.2307894825935364,
-                -0.6764951944351196,
-                186.9346923828125,
-                2.405353009700775,
-                0.0,
-                0.0,
-                0.0,
-                2.5862385034561157,
-                0.0,
-                0.0,
-                0.0,
-                6.484405517578125
-            ]
-        },
-        "content": {
-            "uri": "0/0.glb"
-        },
-        "geometricError": 0.0,
-        "refine": "REPLACE",
-        "transform": [
-            -0.14382095244935905,
-            0.9896037255571338,
-            0.0,
-            0.0,
-            -0.7120020847592599,
-            -0.1034765889935951,
-            0.6945110703428119,
-            0.0,
-            0.6872907426519194,
-            0.09988524362332703,
-            0.7194820172674795,
-            0.0,
-            4391456.686631473,
-            638218.5788113032,
-            4566368.395700517,
-            1.0
-        ]
+    "version": "1.1"
+  },
+  "extensions": {
+    "3DTILES_content_gltf": {
+      "extensionsRequired": [
+        "KHR_gaussian_splatting",
+        "KHR_gaussian_splatting_compression_spz_2"
+      ],
+      "extensionsUsed": [
+        "KHR_gaussian_splatting",
+        "KHR_gaussian_splatting_compression_spz_2"
+      ]
     }
+  },
+  "extensionsUsed": [
+    "3DTILES_content_gltf"
+  ],
+  "geometricError": 76.94345372195917,
+  "root": {
+    "boundingVolume": {
+      "box": [
+        0.759602474620948,
+        -1.6211592734702087,
+        2566.3544788548998,
+        8.432663940269968,
+        0.0,
+        0.0,
+        0.0,
+        8.127358416707006,
+        0.0,
+        0.0,
+        0.0,
+        36.64573633729674
+      ]
+    },
+    "content": {
+      "uri": "0/0.glb"
+    },
+    "geometricError": 0.0,
+    "refine": "REPLACE",
+    "transform": [
+      0.9984683783609064,
+      -0.0553253776610889,
+      0.0,
+      0.0,
+      0.038789672094630565,
+      0.7000451263203326,
+      0.7130443060946077,
+      0.0,
+      -0.03944944552377324,
+      -0.7119521920057605,
+      0.7011189753145034,
+      0.0,
+      -252040.29496225834,
+      -4548622.6254820945,
+      4449422.940203034,
+      1.0
+    ]
+  }
 }
diff --git a/Specs/Data/Cesium3DTiles/GaussianSplats/tower_legacy/0/0.glb b/Specs/Data/Cesium3DTiles/GaussianSplats/tower_legacy/0/0.glb
diff --git a/Specs/Data/Cesium3DTiles/GaussianSplats/tower_legacy/tileset.json b/Specs/Data/Cesium3DTiles/GaussianSplats/tower_legacy/tileset.json
@@ -0,0 +1,66 @@
+{
+    "asset": {
+        "extras": {
+            "ion": {
+                "georeferenced": true,
+                "movable": true
+            }
+        },
+        "version": "1.1"
+    },
+    "extensions": {
+        "3DTILES_content_gltf": {
+            "extensionsRequired": [
+                "KHR_spz_gaussian_splats_compression"
+            ],
+            "extensionsUsed": [
+                "KHR_spz_gaussian_splats_compression"
+            ]
+        }
+    },
+    "extensionsUsed": [
+        "3DTILES_content_gltf"
+    ],
+    "geometricError": 14.76778488662848,
+    "root": {
+        "boundingVolume": {
+            "box": [
+                1.2307894825935364,
+                -0.6764951944351196,
+                186.9346923828125,
+                2.405353009700775,
+                0.0,
+                0.0,
+                0.0,
+                2.5862385034561157,
+                0.0,
+                0.0,
+                0.0,
+                6.484405517578125
+            ]
+        },
+        "content": {
+            "uri": "0/0.glb"
+        },
+        "geometricError": 0.0,
+        "refine": "REPLACE",
+        "transform": [
+            -0.14382095244935905,
+            0.9896037255571338,
+            0.0,
+            0.0,
+            -0.7120020847592599,
+            -0.1034765889935951,
+            0.6945110703428119,
+            0.0,
+            0.6872907426519194,
+            0.09988524362332703,
+            0.7194820172674795,
+            0.0,
+            4391456.686631473,
+            638218.5788113032,
+            4566368.395700517,
+            1.0
+        ]
+    }
+}
diff --git a/packages/engine/Source/Scene/Cesium3DTileContentFactory.js b/packages/engine/Source/Scene/Cesium3DTileContentFactory.js
@@ -93,28 +93,19 @@ const Cesium3DTileContentFactory = {
     const dataView = new DataView(arrayBuffer, byteOffset);
     const byteLength = dataView.getUint32(8, true);
     const glb = new Uint8Array(arrayBuffer, byteOffset, byteLength);
-    let hasGaussianSplatExtension = false;
-    if (tileset.isGltfExtensionRequired instanceof Function) {
-      hasGaussianSplatExtension = tileset.isGltfExtensionRequired(
-        "KHR_spz_gaussian_splats_compression",
-      );
-    }
-    if (hasGaussianSplatExtension) {
+
+    if (
+      GaussianSplat3DTileContent.tilesetRequiresGaussianSplattingExt(tileset)
+    ) {
       return GaussianSplat3DTileContent.fromGltf(tileset, tile, resource, glb);
     }
 
     return Model3DTileContent.fromGltf(tileset, tile, resource, glb);
   },
   gltf: function (tileset, tile, resource, json) {
-    const forceGaussianSplats =
-      tileset.debugTreatTilesetAsGaussianSplats ?? false;
-    let hasGaussianSplatExtension = false;
-    if (tileset.isGltfExtensionRequired instanceof Function) {
-      hasGaussianSplatExtension = tileset.isGltfExtensionRequired(
-        "KHR_spz_gaussian_splats_compression",
-      );
-    }
-    if (forceGaussianSplats || hasGaussianSplatExtension) {
+    if (
+      GaussianSplat3DTileContent.tilesetRequiresGaussianSplattingExt(tileset)
+    ) {
       return GaussianSplat3DTileContent.fromGltf(tileset, tile, resource, json);
     }
 

diff --git a/packages/engine/Source/Scene/Cesium3DTileset.js b/packages/engine/Source/Scene/Cesium3DTileset.js
@@ -147,7 +147,7 @@ import ImageryLayerCollection from "./ImageryLayerCollection.js";
  *
  * @alias Cesium3DTileset
  * @constructor
- * @experimental Support for loading Gaussian splats content encoded with SPZ compression using the draft glTF extension {@link https://github.com/KhronosGroup/glTF/pull/2490 | KHR_spz_gaussian_splats_compression} is experimental and is subject change without Cesium's standard deprecation policy.
+ * @experimental Support for loading Gaussian splats content encoded with SPZ compression using the draft glTF extensions {@link https://github.com/CesiumGS/glTF/tree/draft-splat-spz/extensions/2.0/Khronos/KHR_gaussian_splatting | KHR_gaussian_splatting} and {@link https://github.com/CesiumGS/glTF/tree/draft-splat-spz/extensions/2.0/Khronos/KHR_gaussian_splatting_compression_spz_2 | KHR_gaussian_splatting_compression_spz_2} is experimental and is subject change without Cesium's standard deprecation policy.
  * @param {Cesium3DTileset.ConstructorOptions} options An object describing initialization options
  *
  * @exception {DeveloperError} The tileset must be 3D Tiles version 0.0 or 1.0.

diff --git a/packages/engine/Source/Scene/GaussianSplat3DTileContent.js b/packages/engine/Source/Scene/GaussianSplat3DTileContent.js
@@ -7,9 +7,10 @@ import GaussianSplatPrimitive from "./GaussianSplatPrimitive.js";
 import destroyObject from "../Core/destroyObject.js";
 import ModelUtility from "./Model/ModelUtility.js";
 import VertexAttributeSemantic from "./VertexAttributeSemantic.js";
+import deprecationWarning from "../Core/deprecationWarning.js";
 
 /**
- * Represents the contents of a glTF or glb using the {@link https://github.com/CesiumGS/glTF/tree/draft-spz-splat-compression/extensions/2.0/Khronos/KHR_spz_gaussian_splats_compression|KHR_spz_gaussian_splats_compression} extension.
+ * Represents the contents of a glTF or glb using the {@link https://github.com/CesiumGS/glTF/tree/draft-splat-spz/extensions/2.0/Khronos/KHR_gaussian_splatting | KHR_gaussian_splatting} and {@link https://github.com/CesiumGS/glTF/tree/draft-splat-spz/extensions/2.0/Khronos/KHR_gaussian_splatting_compression_spz_2 | KHR_gaussian_splatting_compression_spz_2} extensions.
  * <p>
  * Implements the {@link Cesium3DTileContent} interface.
  * </p>
@@ -80,6 +81,43 @@ function GaussianSplat3DTileContent(loader, tileset, tile, resource) {
   this._transformed = false;
 }
 
+/**
+ * Performs checks to ensure that the provided tileset has the Gaussian Splatting extensions.
+ *
+ * @param {Cesium3DTileset} tileset The tileset to check for the extensions.
+ * @returns {boolean} Returns <code>true</code> if the necessary extensions are included in the tileset.
+ * @static
+ */
+GaussianSplat3DTileContent.tilesetRequiresGaussianSplattingExt = function (
+  tileset,
+) {
+  let hasGaussianSplatExtension = false;
+  let hasLegacyGaussianSplatExtension = false;
+  if (tileset.isGltfExtensionRequired instanceof Function) {
+    hasGaussianSplatExtension =
+      tileset.isGltfExtensionRequired("KHR_gaussian_splatting") &&
+      tileset.isGltfExtensionRequired(
+        "KHR_gaussian_splatting_compression_spz_2",
+      );
+
+    hasLegacyGaussianSplatExtension = tileset.isGltfExtensionRequired(
+      "KHR_spz_gaussian_splats_compression",
+    );
+  }
+
+  if (hasLegacyGaussianSplatExtension) {
+    deprecationWarning(
+      "KHR_spz_gaussian_splats_compression",
+      "Support for the original KHR_spz_gaussian_splats_compression extension has been deprecated in favor " +
+        "of the up to date KHR_gaussian_splatting and KHR_gaussian_splatting_compression_spz_2 extensions and will be " +
+        "removed in CesiumJS 1.135.\n\nPlease retile your tileset with the KHR_gaussian_splatting and " +
+        "KHR_gaussian_splatting_compression_spz_2 extensions.",
+    );
+  }
+
+  return hasGaussianSplatExtension || hasLegacyGaussianSplatExtension;
+};
+
 Object.defineProperties(GaussianSplat3DTileContent.prototype, {
   /**
    * Gets the number of features in the tile. Currently this is always zero.

diff --git a/packages/engine/Source/Scene/GaussianSplatPrimitive.js b/packages/engine/Source/Scene/GaussianSplatPrimitive.js
@@ -64,7 +64,7 @@ function createGaussianSplatTexture(context, splatTextureData) {
 /** A primitive that renders Gaussian splats.
  * <p>
  * This primitive is used to render Gaussian splats in a 3D Tileset.
- * It is designed to work with the KHR_spz_gaussian_splats_compression extension.
+ * It is designed to work with the KHR_gaussian_splatting and KHR_gaussian_splatting_compression_spz_2 extensions.
  * </p>
  * @alias GaussianSplatPrimitive
  * @constructor