diff --git a/docs/modules/geospatial/api-reference/ellipsoid-tangent-plane.md b/docs/modules/geospatial/api-reference/ellipsoid-tangent-plane.md
new file mode 100644
index 00000000..c5021255
--- /dev/null
+++ b/docs/modules/geospatial/api-reference/ellipsoid-tangent-plane.md
@@ -0,0 +1,13 @@
+# EllipsoidTangentPlane
+
+TBA
+
+Function to convert a geospatial region to an oriented bounding box using ellipsoid math. Computes an `OrientedBoundingBox` that bounds a region on the surface of the WGS84 ellipsoid. There are no guarantees about the orientation of the bounding box.
+
+ Parameters:
+
+ - `region: number[]` - The cartographic region (west, south, east, north, minimum height, maximum height) on the surface of the ellipsoid.
+
+ Returns:
+
+ - `OrientedBoundingBox` - The modified result parameter or a new OrientedBoundingBox instance if none was provided.
diff --git a/docs/modules/geospatial/api-reference/image.png b/docs/modules/geospatial/api-reference/image.png
new file mode 100644
index 00000000..40584ce0
Binary files /dev/null and b/docs/modules/geospatial/api-reference/image.png differ
diff --git a/docs/modules/geospatial/api-reference/make-obb-from-region.md b/docs/modules/geospatial/api-reference/make-obb-from-region.md
new file mode 100644
index 00000000..e69de29b
diff --git a/docs/table-of-contents.json b/docs/table-of-contents.json
index bf038978..ad244ded 100644
--- a/docs/table-of-contents.json
+++ b/docs/table-of-contents.json
@@ -113,6 +113,7 @@
         "items": [
           "modules/geospatial/README",
           "modules/geospatial/api-reference/ellipsoid",
+          "modules/geospatial/api-reference/ellipsoid-tangent-plane",
           "modules/geospatial/api-reference/helpers"
         ]
       },
diff --git a/docs/whats-new.md b/docs/whats-new.md
index 8731eff1..09b4f124 100644
--- a/docs/whats-new.md
+++ b/docs/whats-new.md
@@ -55,7 +55,14 @@ Goal: Stronger type guarantees for math classes via the new sized array types.
 
 Release Date: TBD, maybe Q1, 2024.
 
-Goal: Minor functionality additions, as required.
+Goals:
+
+- Functionality additions to improve 3D Tiles support in loaders.gl.
+
+**`@math.gl/geopspatial`**
+
+- `makeOBBFromRegion()` - New function that creates a cartesian oriented bounding box from a geospatial region.
+- `EllipsoidTangentPlane` - New helper class for doing math on the ellipsoid surface.
 
 ## v4.1
 
diff --git a/modules/geospatial/src/make-obb-from-region.ts b/modules/geospatial/src/make-obb-from-region.ts
index ec52a800..fcc7f304 100644
--- a/modules/geospatial/src/make-obb-from-region.ts
+++ b/modules/geospatial/src/make-obb-from-region.ts
@@ -49,9 +49,9 @@ const VECTOR3_UNIT_Z = new Vector3(0, 0, 1);
  * Computes an OrientedBoundingBox that bounds a region on the surface of the WGS84 ellipsoid.
  * There are no guarantees about the orientation of the bounding box.
  *
- * @param {number[]} region The cartographic region ([west, south, east, north, minimum height, maximum height])
+ * @param region The cartographic region ([west, south, east, north, minimum height, maximum height])
  *                          on the surface of the ellipsoid.
- * @returns {OrientedBoundingBox} The modified result parameter or a new OrientedBoundingBox instance if none was provided.
+ * @returns The modified result parameter or a new OrientedBoundingBox instance if none was provided.
  */
 // eslint-disable-next-line max-statements
 export function makeOBBfromRegion(region: number[]): OrientedBoundingBox {