diff --git a/web/maplibre-demo.html b/web/maplibre-demo.html
index 1ebfdfb..6de32ad 100644
--- a/web/maplibre-demo.html
+++ b/web/maplibre-demo.html
@@ -138,6 +138,14 @@
     </div>
 
     <script src="./vendor/maplibre/maplibre-gl.js"></script>
+    <script type="importmap">
+      {
+        "imports": {
+          "three": "./vendor/three/three.module.js",
+          "three/": "./vendor/three/"
+        }
+      }
+    </script>
     <script type="module" src="./maplibre-demo.js"></script>
   </body>
 </html>
diff --git a/web/vendor/three/GLTFLoader.js b/web/vendor/three/GLTFLoader.js
index 3cb312c..7e3f2ba 100644
--- a/web/vendor/three/GLTFLoader.js
+++ b/web/vendor/three/GLTFLoader.js
@@ -65,7 +65,7 @@ import {
 	SRGBColorSpace,
 	InstancedBufferAttribute
 } from './three.module.js';
-import { toTrianglesDrawMode } from '../utils/BufferGeometryUtils.js';
+import { toTrianglesDrawMode } from './utils/BufferGeometryUtils.js';
 
 class GLTFLoader extends Loader {
 
diff --git a/web/vendor/three/utils/BufferGeometryUtils.js b/web/vendor/three/utils/BufferGeometryUtils.js
new file mode 100644
index 0000000..b37d3f6
--- /dev/null
+++ b/web/vendor/three/utils/BufferGeometryUtils.js
@@ -0,0 +1,1373 @@
+import {
+	BufferAttribute,
+	BufferGeometry,
+	Float32BufferAttribute,
+	InstancedBufferAttribute,
+	InterleavedBuffer,
+	InterleavedBufferAttribute,
+	TriangleFanDrawMode,
+	TriangleStripDrawMode,
+	TrianglesDrawMode,
+	Vector3,
+} from '../three.module.js';
+
+function computeMikkTSpaceTangents( geometry, MikkTSpace, negateSign = true ) {
+
+	if ( ! MikkTSpace || ! MikkTSpace.isReady ) {
+
+		throw new Error( 'BufferGeometryUtils: Initialized MikkTSpace library required.' );
+
+	}
+
+	if ( ! geometry.hasAttribute( 'position' ) || ! geometry.hasAttribute( 'normal' ) || ! geometry.hasAttribute( 'uv' ) ) {
+
+		throw new Error( 'BufferGeometryUtils: Tangents require "position", "normal", and "uv" attributes.' );
+
+	}
+
+	function getAttributeArray( attribute ) {
+
+		if ( attribute.normalized || attribute.isInterleavedBufferAttribute ) {
+
+			const dstArray = new Float32Array( attribute.count * attribute.itemSize );
+
+			for ( let i = 0, j = 0; i < attribute.count; i ++ ) {
+
+				dstArray[ j ++ ] = attribute.getX( i );
+				dstArray[ j ++ ] = attribute.getY( i );
+
+				if ( attribute.itemSize > 2 ) {
+
+					dstArray[ j ++ ] = attribute.getZ( i );
+
+				}
+
+			}
+
+			return dstArray;
+
+		}
+
+		if ( attribute.array instanceof Float32Array ) {
+
+			return attribute.array;
+
+		}
+
+		return new Float32Array( attribute.array );
+
+	}
+
+	// MikkTSpace algorithm requires non-indexed input.
+
+	const _geometry = geometry.index ? geometry.toNonIndexed() : geometry;
+
+	// Compute vertex tangents.
+
+	const tangents = MikkTSpace.generateTangents(
+
+		getAttributeArray( _geometry.attributes.position ),
+		getAttributeArray( _geometry.attributes.normal ),
+		getAttributeArray( _geometry.attributes.uv )
+
+	);
+
+	// Texture coordinate convention of glTF differs from the apparent
+	// default of the MikkTSpace library; .w component must be flipped.
+
+	if ( negateSign ) {
+
+		for ( let i = 3; i < tangents.length; i += 4 ) {
+
+			tangents[ i ] *= - 1;
+
+		}
+
+	}
+
+	//
+
+	_geometry.setAttribute( 'tangent', new BufferAttribute( tangents, 4 ) );
+
+	if ( geometry !== _geometry ) {
+
+		geometry.copy( _geometry );
+
+	}
+
+	return geometry;
+
+}
+
+/**
+ * @param  {Array<BufferGeometry>} geometries
+ * @param  {Boolean} useGroups
+ * @return {BufferGeometry}
+ */
+function mergeGeometries( geometries, useGroups = false ) {
+
+	const isIndexed = geometries[ 0 ].index !== null;
+
+	const attributesUsed = new Set( Object.keys( geometries[ 0 ].attributes ) );
+	const morphAttributesUsed = new Set( Object.keys( geometries[ 0 ].morphAttributes ) );
+
+	const attributes = {};
+	const morphAttributes = {};
+
+	const morphTargetsRelative = geometries[ 0 ].morphTargetsRelative;
+
+	const mergedGeometry = new BufferGeometry();
+
+	let offset = 0;
+
+	for ( let i = 0; i < geometries.length; ++ i ) {
+
+		const geometry = geometries[ i ];
+		let attributesCount = 0;
+
+		// ensure that all geometries are indexed, or none
+
+		if ( isIndexed !== ( geometry.index !== null ) ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. All geometries must have compatible attributes; make sure index attribute exists among all geometries, or in none of them.' );
+			return null;
+
+		}
+
+		// gather attributes, exit early if they're different
+
+		for ( const name in geometry.attributes ) {
+
+			if ( ! attributesUsed.has( name ) ) {
+
+				console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. All geometries must have compatible attributes; make sure "' + name + '" attribute exists among all geometries, or in none of them.' );
+				return null;
+
+			}
+
+			if ( attributes[ name ] === undefined ) attributes[ name ] = [];
+
+			attributes[ name ].push( geometry.attributes[ name ] );
+
+			attributesCount ++;
+
+		}
+
+		// ensure geometries have the same number of attributes
+
+		if ( attributesCount !== attributesUsed.size ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. Make sure all geometries have the same number of attributes.' );
+			return null;
+
+		}
+
+		// gather morph attributes, exit early if they're different
+
+		if ( morphTargetsRelative !== geometry.morphTargetsRelative ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. .morphTargetsRelative must be consistent throughout all geometries.' );
+			return null;
+
+		}
+
+		for ( const name in geometry.morphAttributes ) {
+
+			if ( ! morphAttributesUsed.has( name ) ) {
+
+				console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '.  .morphAttributes must be consistent throughout all geometries.' );
+				return null;
+
+			}
+
+			if ( morphAttributes[ name ] === undefined ) morphAttributes[ name ] = [];
+
+			morphAttributes[ name ].push( geometry.morphAttributes[ name ] );
+
+		}
+
+		if ( useGroups ) {
+
+			let count;
+
+			if ( isIndexed ) {
+
+				count = geometry.index.count;
+
+			} else if ( geometry.attributes.position !== undefined ) {
+
+				count = geometry.attributes.position.count;
+
+			} else {
+
+				console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. The geometry must have either an index or a position attribute' );
+				return null;
+
+			}
+
+			mergedGeometry.addGroup( offset, count, i );
+
+			offset += count;
+
+		}
+
+	}
+
+	// merge indices
+
+	if ( isIndexed ) {
+
+		let indexOffset = 0;
+		const mergedIndex = [];
+
+		for ( let i = 0; i < geometries.length; ++ i ) {
+
+			const index = geometries[ i ].index;
+
+			for ( let j = 0; j < index.count; ++ j ) {
+
+				mergedIndex.push( index.getX( j ) + indexOffset );
+
+			}
+
+			indexOffset += geometries[ i ].attributes.position.count;
+
+		}
+
+		mergedGeometry.setIndex( mergedIndex );
+
+	}
+
+	// merge attributes
+
+	for ( const name in attributes ) {
+
+		const mergedAttribute = mergeAttributes( attributes[ name ] );
+
+		if ( ! mergedAttribute ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed while trying to merge the ' + name + ' attribute.' );
+			return null;
+
+		}
+
+		mergedGeometry.setAttribute( name, mergedAttribute );
+
+	}
+
+	// merge morph attributes
+
+	for ( const name in morphAttributes ) {
+
+		const numMorphTargets = morphAttributes[ name ][ 0 ].length;
+
+		if ( numMorphTargets === 0 ) break;
+
+		mergedGeometry.morphAttributes = mergedGeometry.morphAttributes || {};
+		mergedGeometry.morphAttributes[ name ] = [];
+
+		for ( let i = 0; i < numMorphTargets; ++ i ) {
+
+			const morphAttributesToMerge = [];
+
+			for ( let j = 0; j < morphAttributes[ name ].length; ++ j ) {
+
+				morphAttributesToMerge.push( morphAttributes[ name ][ j ][ i ] );
+
+			}
+
+			const mergedMorphAttribute = mergeAttributes( morphAttributesToMerge );
+
+			if ( ! mergedMorphAttribute ) {
+
+				console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed while trying to merge the ' + name + ' morphAttribute.' );
+				return null;
+
+			}
+
+			mergedGeometry.morphAttributes[ name ].push( mergedMorphAttribute );
+
+		}
+
+	}
+
+	return mergedGeometry;
+
+}
+
+/**
+ * @param {Array<BufferAttribute>} attributes
+ * @return {BufferAttribute}
+ */
+function mergeAttributes( attributes ) {
+
+	let TypedArray;
+	let itemSize;
+	let normalized;
+	let gpuType = - 1;
+	let arrayLength = 0;
+
+	for ( let i = 0; i < attributes.length; ++ i ) {
+
+		const attribute = attributes[ i ];
+
+		if ( TypedArray === undefined ) TypedArray = attribute.array.constructor;
+		if ( TypedArray !== attribute.array.constructor ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.array must be of consistent array types across matching attributes.' );
+			return null;
+
+		}
+
+		if ( itemSize === undefined ) itemSize = attribute.itemSize;
+		if ( itemSize !== attribute.itemSize ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.itemSize must be consistent across matching attributes.' );
+			return null;
+
+		}
+
+		if ( normalized === undefined ) normalized = attribute.normalized;
+		if ( normalized !== attribute.normalized ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.normalized must be consistent across matching attributes.' );
+			return null;
+
+		}
+
+		if ( gpuType === - 1 ) gpuType = attribute.gpuType;
+		if ( gpuType !== attribute.gpuType ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.gpuType must be consistent across matching attributes.' );
+			return null;
+
+		}
+
+		arrayLength += attribute.count * itemSize;
+
+	}
+
+	const array = new TypedArray( arrayLength );
+	const result = new BufferAttribute( array, itemSize, normalized );
+	let offset = 0;
+
+	for ( let i = 0; i < attributes.length; ++ i ) {
+
+		const attribute = attributes[ i ];
+		if ( attribute.isInterleavedBufferAttribute ) {
+
+			const tupleOffset = offset / itemSize;
+			for ( let j = 0, l = attribute.count; j < l; j ++ ) {
+
+				for ( let c = 0; c < itemSize; c ++ ) {
+
+					const value = attribute.getComponent( j, c );
+					result.setComponent( j + tupleOffset, c, value );
+
+				}
+
+			}
+
+		} else {
+
+			array.set( attribute.array, offset );
+
+		}
+
+		offset += attribute.count * itemSize;
+
+	}
+
+	if ( gpuType !== undefined ) {
+
+		result.gpuType = gpuType;
+
+	}
+
+	return result;
+
+}
+
+/**
+ * @param {BufferAttribute}
+ * @return {BufferAttribute}
+ */
+export function deepCloneAttribute( attribute ) {
+
+	if ( attribute.isInstancedInterleavedBufferAttribute || attribute.isInterleavedBufferAttribute ) {
+
+		return deinterleaveAttribute( attribute );
+
+	}
+
+	if ( attribute.isInstancedBufferAttribute ) {
+
+		return new InstancedBufferAttribute().copy( attribute );
+
+	}
+
+	return new BufferAttribute().copy( attribute );
+
+}
+
+/**
+ * @param {Array<BufferAttribute>} attributes
+ * @return {Array<InterleavedBufferAttribute>}
+ */
+function interleaveAttributes( attributes ) {
+
+	// Interleaves the provided attributes into an InterleavedBuffer and returns
+	// a set of InterleavedBufferAttributes for each attribute
+	let TypedArray;
+	let arrayLength = 0;
+	let stride = 0;
+
+	// calculate the length and type of the interleavedBuffer
+	for ( let i = 0, l = attributes.length; i < l; ++ i ) {
+
+		const attribute = attributes[ i ];
+
+		if ( TypedArray === undefined ) TypedArray = attribute.array.constructor;
+		if ( TypedArray !== attribute.array.constructor ) {
+
+			console.error( 'AttributeBuffers of different types cannot be interleaved' );
+			return null;
+
+		}
+
+		arrayLength += attribute.array.length;
+		stride += attribute.itemSize;
+
+	}
+
+	// Create the set of buffer attributes
+	const interleavedBuffer = new InterleavedBuffer( new TypedArray( arrayLength ), stride );
+	let offset = 0;
+	const res = [];
+	const getters = [ 'getX', 'getY', 'getZ', 'getW' ];
+	const setters = [ 'setX', 'setY', 'setZ', 'setW' ];
+
+	for ( let j = 0, l = attributes.length; j < l; j ++ ) {
+
+		const attribute = attributes[ j ];
+		const itemSize = attribute.itemSize;
+		const count = attribute.count;
+		const iba = new InterleavedBufferAttribute( interleavedBuffer, itemSize, offset, attribute.normalized );
+		res.push( iba );
+
+		offset += itemSize;
+
+		// Move the data for each attribute into the new interleavedBuffer
+		// at the appropriate offset
+		for ( let c = 0; c < count; c ++ ) {
+
+			for ( let k = 0; k < itemSize; k ++ ) {
+
+				iba[ setters[ k ] ]( c, attribute[ getters[ k ] ]( c ) );
+
+			}
+
+		}
+
+	}
+
+	return res;
+
+}
+
+// returns a new, non-interleaved version of the provided attribute
+export function deinterleaveAttribute( attribute ) {
+
+	const cons = attribute.data.array.constructor;
+	const count = attribute.count;
+	const itemSize = attribute.itemSize;
+	const normalized = attribute.normalized;
+
+	const array = new cons( count * itemSize );
+	let newAttribute;
+	if ( attribute.isInstancedInterleavedBufferAttribute ) {
+
+		newAttribute = new InstancedBufferAttribute( array, itemSize, normalized, attribute.meshPerAttribute );
+
+	} else {
+
+		newAttribute = new BufferAttribute( array, itemSize, normalized );
+
+	}
+
+	for ( let i = 0; i < count; i ++ ) {
+
+		newAttribute.setX( i, attribute.getX( i ) );
+
+		if ( itemSize >= 2 ) {
+
+			newAttribute.setY( i, attribute.getY( i ) );
+
+		}
+
+		if ( itemSize >= 3 ) {
+
+			newAttribute.setZ( i, attribute.getZ( i ) );
+
+		}
+
+		if ( itemSize >= 4 ) {
+
+			newAttribute.setW( i, attribute.getW( i ) );
+
+		}
+
+	}
+
+	return newAttribute;
+
+}
+
+// deinterleaves all attributes on the geometry
+export function deinterleaveGeometry( geometry ) {
+
+	const attributes = geometry.attributes;
+	const morphTargets = geometry.morphTargets;
+	const attrMap = new Map();
+
+	for ( const key in attributes ) {
+
+		const attr = attributes[ key ];
+		if ( attr.isInterleavedBufferAttribute ) {
+
+			if ( ! attrMap.has( attr ) ) {
+
+				attrMap.set( attr, deinterleaveAttribute( attr ) );
+
+			}
+
+			attributes[ key ] = attrMap.get( attr );
+
+		}
+
+	}
+
+	for ( const key in morphTargets ) {
+
+		const attr = morphTargets[ key ];
+		if ( attr.isInterleavedBufferAttribute ) {
+
+			if ( ! attrMap.has( attr ) ) {
+
+				attrMap.set( attr, deinterleaveAttribute( attr ) );
+
+			}
+
+			morphTargets[ key ] = attrMap.get( attr );
+
+		}
+
+	}
+
+}
+
+/**
+ * @param {BufferGeometry} geometry
+ * @return {number}
+ */
+function estimateBytesUsed( geometry ) {
+
+	// Return the estimated memory used by this geometry in bytes
+	// Calculate using itemSize, count, and BYTES_PER_ELEMENT to account
+	// for InterleavedBufferAttributes.
+	let mem = 0;
+	for ( const name in geometry.attributes ) {
+
+		const attr = geometry.getAttribute( name );
+		mem += attr.count * attr.itemSize * attr.array.BYTES_PER_ELEMENT;
+
+	}
+
+	const indices = geometry.getIndex();
+	mem += indices ? indices.count * indices.itemSize * indices.array.BYTES_PER_ELEMENT : 0;
+	return mem;
+
+}
+
+/**
+ * @param {BufferGeometry} geometry
+ * @param {number} tolerance
+ * @return {BufferGeometry}
+ */
+function mergeVertices( geometry, tolerance = 1e-4 ) {
+
+	tolerance = Math.max( tolerance, Number.EPSILON );
+
+	// Generate an index buffer if the geometry doesn't have one, or optimize it
+	// if it's already available.
+	const hashToIndex = {};
+	const indices = geometry.getIndex();
+	const positions = geometry.getAttribute( 'position' );
+	const vertexCount = indices ? indices.count : positions.count;
+
+	// next value for triangle indices
+	let nextIndex = 0;
+
+	// attributes and new attribute arrays
+	const attributeNames = Object.keys( geometry.attributes );
+	const tmpAttributes = {};
+	const tmpMorphAttributes = {};
+	const newIndices = [];
+	const getters = [ 'getX', 'getY', 'getZ', 'getW' ];
+	const setters = [ 'setX', 'setY', 'setZ', 'setW' ];
+
+	// Initialize the arrays, allocating space conservatively. Extra
+	// space will be trimmed in the last step.
+	for ( let i = 0, l = attributeNames.length; i < l; i ++ ) {
+
+		const name = attributeNames[ i ];
+		const attr = geometry.attributes[ name ];
+
+		tmpAttributes[ name ] = new attr.constructor(
+			new attr.array.constructor( attr.count * attr.itemSize ),
+			attr.itemSize,
+			attr.normalized
+		);
+
+		const morphAttributes = geometry.morphAttributes[ name ];
+		if ( morphAttributes ) {
+
+			if ( ! tmpMorphAttributes[ name ] ) tmpMorphAttributes[ name ] = [];
+			morphAttributes.forEach( ( morphAttr, i ) => {
+
+				const array = new morphAttr.array.constructor( morphAttr.count * morphAttr.itemSize );
+				tmpMorphAttributes[ name ][ i ] = new morphAttr.constructor( array, morphAttr.itemSize, morphAttr.normalized );
+
+			} );
+
+		}
+
+	}
+
+	// convert the error tolerance to an amount of decimal places to truncate to
+	const halfTolerance = tolerance * 0.5;
+	const exponent = Math.log10( 1 / tolerance );
+	const hashMultiplier = Math.pow( 10, exponent );
+	const hashAdditive = halfTolerance * hashMultiplier;
+	for ( let i = 0; i < vertexCount; i ++ ) {
+
+		const index = indices ? indices.getX( i ) : i;
+
+		// Generate a hash for the vertex attributes at the current index 'i'
+		let hash = '';
+		for ( let j = 0, l = attributeNames.length; j < l; j ++ ) {
+
+			const name = attributeNames[ j ];
+			const attribute = geometry.getAttribute( name );
+			const itemSize = attribute.itemSize;
+
+			for ( let k = 0; k < itemSize; k ++ ) {
+
+				// double tilde truncates the decimal value
+				hash += `${ ~ ~ ( attribute[ getters[ k ] ]( index ) * hashMultiplier + hashAdditive ) },`;
+
+			}
+
+		}
+
+		// Add another reference to the vertex if it's already
+		// used by another index
+		if ( hash in hashToIndex ) {
+
+			newIndices.push( hashToIndex[ hash ] );
+
+		} else {
+
+			// copy data to the new index in the temporary attributes
+			for ( let j = 0, l = attributeNames.length; j < l; j ++ ) {
+
+				const name = attributeNames[ j ];
+				const attribute = geometry.getAttribute( name );
+				const morphAttributes = geometry.morphAttributes[ name ];
+				const itemSize = attribute.itemSize;
+				const newArray = tmpAttributes[ name ];
+				const newMorphArrays = tmpMorphAttributes[ name ];
+
+				for ( let k = 0; k < itemSize; k ++ ) {
+
+					const getterFunc = getters[ k ];
+					const setterFunc = setters[ k ];
+					newArray[ setterFunc ]( nextIndex, attribute[ getterFunc ]( index ) );
+
+					if ( morphAttributes ) {
+
+						for ( let m = 0, ml = morphAttributes.length; m < ml; m ++ ) {
+
+							newMorphArrays[ m ][ setterFunc ]( nextIndex, morphAttributes[ m ][ getterFunc ]( index ) );
+
+						}
+
+					}
+
+				}
+
+			}
+
+			hashToIndex[ hash ] = nextIndex;
+			newIndices.push( nextIndex );
+			nextIndex ++;
+
+		}
+
+	}
+
+	// generate result BufferGeometry
+	const result = geometry.clone();
+	for ( const name in geometry.attributes ) {
+
+		const tmpAttribute = tmpAttributes[ name ];
+
+		result.setAttribute( name, new tmpAttribute.constructor(
+			tmpAttribute.array.slice( 0, nextIndex * tmpAttribute.itemSize ),
+			tmpAttribute.itemSize,
+			tmpAttribute.normalized,
+		) );
+
+		if ( ! ( name in tmpMorphAttributes ) ) continue;
+
+		for ( let j = 0; j < tmpMorphAttributes[ name ].length; j ++ ) {
+
+			const tmpMorphAttribute = tmpMorphAttributes[ name ][ j ];
+
+			result.morphAttributes[ name ][ j ] = new tmpMorphAttribute.constructor(
+				tmpMorphAttribute.array.slice( 0, nextIndex * tmpMorphAttribute.itemSize ),
+				tmpMorphAttribute.itemSize,
+				tmpMorphAttribute.normalized,
+			);
+
+		}
+
+	}
+
+	// indices
+
+	result.setIndex( newIndices );
+
+	return result;
+
+}
+
+/**
+ * @param {BufferGeometry} geometry
+ * @param {number} drawMode
+ * @return {BufferGeometry}
+ */
+function toTrianglesDrawMode( geometry, drawMode ) {
+
+	if ( drawMode === TrianglesDrawMode ) {
+
+		console.warn( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Geometry already defined as triangles.' );
+		return geometry;
+
+	}
+
+	if ( drawMode === TriangleFanDrawMode || drawMode === TriangleStripDrawMode ) {
+
+		let index = geometry.getIndex();
+
+		// generate index if not present
+
+		if ( index === null ) {
+
+			const indices = [];
+
+			const position = geometry.getAttribute( 'position' );
+
+			if ( position !== undefined ) {
+
+				for ( let i = 0; i < position.count; i ++ ) {
+
+					indices.push( i );
+
+				}
+
+				geometry.setIndex( indices );
+				index = geometry.getIndex();
+
+			} else {
+
+				console.error( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Undefined position attribute. Processing not possible.' );
+				return geometry;
+
+			}
+
+		}
+
+		//
+
+		const numberOfTriangles = index.count - 2;
+		const newIndices = [];
+
+		if ( drawMode === TriangleFanDrawMode ) {
+
+			// gl.TRIANGLE_FAN
+
+			for ( let i = 1; i <= numberOfTriangles; i ++ ) {
+
+				newIndices.push( index.getX( 0 ) );
+				newIndices.push( index.getX( i ) );
+				newIndices.push( index.getX( i + 1 ) );
+
+			}
+
+		} else {
+
+			// gl.TRIANGLE_STRIP
+
+			for ( let i = 0; i < numberOfTriangles; i ++ ) {
+
+				if ( i % 2 === 0 ) {
+
+					newIndices.push( index.getX( i ) );
+					newIndices.push( index.getX( i + 1 ) );
+					newIndices.push( index.getX( i + 2 ) );
+
+				} else {
+
+					newIndices.push( index.getX( i + 2 ) );
+					newIndices.push( index.getX( i + 1 ) );
+					newIndices.push( index.getX( i ) );
+
+				}
+
+			}
+
+		}
+
+		if ( ( newIndices.length / 3 ) !== numberOfTriangles ) {
+
+			console.error( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Unable to generate correct amount of triangles.' );
+
+		}
+
+		// build final geometry
+
+		const newGeometry = geometry.clone();
+		newGeometry.setIndex( newIndices );
+		newGeometry.clearGroups();
+
+		return newGeometry;
+
+	} else {
+
+		console.error( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Unknown draw mode:', drawMode );
+		return geometry;
+
+	}
+
+}
+
+/**
+ * Calculates the morphed attributes of a morphed/skinned BufferGeometry.
+ * Helpful for Raytracing or Decals.
+ * @param {Mesh | Line | Points} object An instance of Mesh, Line or Points.
+ * @return {Object} An Object with original position/normal attributes and morphed ones.
+ */
+function computeMorphedAttributes( object ) {
+
+	const _vA = new Vector3();
+	const _vB = new Vector3();
+	const _vC = new Vector3();
+
+	const _tempA = new Vector3();
+	const _tempB = new Vector3();
+	const _tempC = new Vector3();
+
+	const _morphA = new Vector3();
+	const _morphB = new Vector3();
+	const _morphC = new Vector3();
+
+	function _calculateMorphedAttributeData(
+		object,
+		attribute,
+		morphAttribute,
+		morphTargetsRelative,
+		a,
+		b,
+		c,
+		modifiedAttributeArray
+	) {
+
+		_vA.fromBufferAttribute( attribute, a );
+		_vB.fromBufferAttribute( attribute, b );
+		_vC.fromBufferAttribute( attribute, c );
+
+		const morphInfluences = object.morphTargetInfluences;
+
+		if ( morphAttribute && morphInfluences ) {
+
+			_morphA.set( 0, 0, 0 );
+			_morphB.set( 0, 0, 0 );
+			_morphC.set( 0, 0, 0 );
+
+			for ( let i = 0, il = morphAttribute.length; i < il; i ++ ) {
+
+				const influence = morphInfluences[ i ];
+				const morph = morphAttribute[ i ];
+
+				if ( influence === 0 ) continue;
+
+				_tempA.fromBufferAttribute( morph, a );
+				_tempB.fromBufferAttribute( morph, b );
+				_tempC.fromBufferAttribute( morph, c );
+
+				if ( morphTargetsRelative ) {
+
+					_morphA.addScaledVector( _tempA, influence );
+					_morphB.addScaledVector( _tempB, influence );
+					_morphC.addScaledVector( _tempC, influence );
+
+				} else {
+
+					_morphA.addScaledVector( _tempA.sub( _vA ), influence );
+					_morphB.addScaledVector( _tempB.sub( _vB ), influence );
+					_morphC.addScaledVector( _tempC.sub( _vC ), influence );
+
+				}
+
+			}
+
+			_vA.add( _morphA );
+			_vB.add( _morphB );
+			_vC.add( _morphC );
+
+		}
+
+		if ( object.isSkinnedMesh ) {
+
+			object.applyBoneTransform( a, _vA );
+			object.applyBoneTransform( b, _vB );
+			object.applyBoneTransform( c, _vC );
+
+		}
+
+		modifiedAttributeArray[ a * 3 + 0 ] = _vA.x;
+		modifiedAttributeArray[ a * 3 + 1 ] = _vA.y;
+		modifiedAttributeArray[ a * 3 + 2 ] = _vA.z;
+		modifiedAttributeArray[ b * 3 + 0 ] = _vB.x;
+		modifiedAttributeArray[ b * 3 + 1 ] = _vB.y;
+		modifiedAttributeArray[ b * 3 + 2 ] = _vB.z;
+		modifiedAttributeArray[ c * 3 + 0 ] = _vC.x;
+		modifiedAttributeArray[ c * 3 + 1 ] = _vC.y;
+		modifiedAttributeArray[ c * 3 + 2 ] = _vC.z;
+
+	}
+
+	const geometry = object.geometry;
+	const material = object.material;
+
+	let a, b, c;
+	const index = geometry.index;
+	const positionAttribute = geometry.attributes.position;
+	const morphPosition = geometry.morphAttributes.position;
+	const morphTargetsRelative = geometry.morphTargetsRelative;
+	const normalAttribute = geometry.attributes.normal;
+	const morphNormal = geometry.morphAttributes.position;
+
+	const groups = geometry.groups;
+	const drawRange = geometry.drawRange;
+	let i, j, il, jl;
+	let group;
+	let start, end;
+
+	const modifiedPosition = new Float32Array( positionAttribute.count * positionAttribute.itemSize );
+	const modifiedNormal = new Float32Array( normalAttribute.count * normalAttribute.itemSize );
+
+	if ( index !== null ) {
+
+		// indexed buffer geometry
+
+		if ( Array.isArray( material ) ) {
+
+			for ( i = 0, il = groups.length; i < il; i ++ ) {
+
+				group = groups[ i ];
+
+				start = Math.max( group.start, drawRange.start );
+				end = Math.min( ( group.start + group.count ), ( drawRange.start + drawRange.count ) );
+
+				for ( j = start, jl = end; j < jl; j += 3 ) {
+
+					a = index.getX( j );
+					b = index.getX( j + 1 );
+					c = index.getX( j + 2 );
+
+					_calculateMorphedAttributeData(
+						object,
+						positionAttribute,
+						morphPosition,
+						morphTargetsRelative,
+						a, b, c,
+						modifiedPosition
+					);
+
+					_calculateMorphedAttributeData(
+						object,
+						normalAttribute,
+						morphNormal,
+						morphTargetsRelative,
+						a, b, c,
+						modifiedNormal
+					);
+
+				}
+
+			}
+
+		} else {
+
+			start = Math.max( 0, drawRange.start );
+			end = Math.min( index.count, ( drawRange.start + drawRange.count ) );
+
+			for ( i = start, il = end; i < il; i += 3 ) {
+
+				a = index.getX( i );
+				b = index.getX( i + 1 );
+				c = index.getX( i + 2 );
+
+				_calculateMorphedAttributeData(
+					object,
+					positionAttribute,
+					morphPosition,
+					morphTargetsRelative,
+					a, b, c,
+					modifiedPosition
+				);
+
+				_calculateMorphedAttributeData(
+					object,
+					normalAttribute,
+					morphNormal,
+					morphTargetsRelative,
+					a, b, c,
+					modifiedNormal
+				);
+
+			}
+
+		}
+
+	} else {
+
+		// non-indexed buffer geometry
+
+		if ( Array.isArray( material ) ) {
+
+			for ( i = 0, il = groups.length; i < il; i ++ ) {
+
+				group = groups[ i ];
+
+				start = Math.max( group.start, drawRange.start );
+				end = Math.min( ( group.start + group.count ), ( drawRange.start + drawRange.count ) );
+
+				for ( j = start, jl = end; j < jl; j += 3 ) {
+
+					a = j;
+					b = j + 1;
+					c = j + 2;
+
+					_calculateMorphedAttributeData(
+						object,
+						positionAttribute,
+						morphPosition,
+						morphTargetsRelative,
+						a, b, c,
+						modifiedPosition
+					);
+
+					_calculateMorphedAttributeData(
+						object,
+						normalAttribute,
+						morphNormal,
+						morphTargetsRelative,
+						a, b, c,
+						modifiedNormal
+					);
+
+				}
+
+			}
+
+		} else {
+
+			start = Math.max( 0, drawRange.start );
+			end = Math.min( positionAttribute.count, ( drawRange.start + drawRange.count ) );
+
+			for ( i = start, il = end; i < il; i += 3 ) {
+
+				a = i;
+				b = i + 1;
+				c = i + 2;
+
+				_calculateMorphedAttributeData(
+					object,
+					positionAttribute,
+					morphPosition,
+					morphTargetsRelative,
+					a, b, c,
+					modifiedPosition
+				);
+
+				_calculateMorphedAttributeData(
+					object,
+					normalAttribute,
+					morphNormal,
+					morphTargetsRelative,
+					a, b, c,
+					modifiedNormal
+				);
+
+			}
+
+		}
+
+	}
+
+	const morphedPositionAttribute = new Float32BufferAttribute( modifiedPosition, 3 );
+	const morphedNormalAttribute = new Float32BufferAttribute( modifiedNormal, 3 );
+
+	return {
+
+		positionAttribute: positionAttribute,
+		normalAttribute: normalAttribute,
+		morphedPositionAttribute: morphedPositionAttribute,
+		morphedNormalAttribute: morphedNormalAttribute
+
+	};
+
+}
+
+function mergeGroups( geometry ) {
+
+	if ( geometry.groups.length === 0 ) {
+
+		console.warn( 'THREE.BufferGeometryUtils.mergeGroups(): No groups are defined. Nothing to merge.' );
+		return geometry;
+
+	}
+
+	let groups = geometry.groups;
+
+	// sort groups by material index
+
+	groups = groups.sort( ( a, b ) => {
+
+		if ( a.materialIndex !== b.materialIndex ) return a.materialIndex - b.materialIndex;
+
+		return a.start - b.start;
+
+	} );
+
+	// create index for non-indexed geometries
+
+	if ( geometry.getIndex() === null ) {
+
+		const positionAttribute = geometry.getAttribute( 'position' );
+		const indices = [];
+
+		for ( let i = 0; i < positionAttribute.count; i += 3 ) {
+
+			indices.push( i, i + 1, i + 2 );
+
+		}
+
+		geometry.setIndex( indices );
+
+	}
+
+	// sort index
+
+	const index = geometry.getIndex();
+
+	const newIndices = [];
+
+	for ( let i = 0; i < groups.length; i ++ ) {
+
+		const group = groups[ i ];
+
+		const groupStart = group.start;
+		const groupLength = groupStart + group.count;
+
+		for ( let j = groupStart; j < groupLength; j ++ ) {
+
+			newIndices.push( index.getX( j ) );
+
+		}
+
+	}
+
+	geometry.dispose(); // Required to force buffer recreation
+	geometry.setIndex( newIndices );
+
+	// update groups indices
+
+	let start = 0;
+
+	for ( let i = 0; i < groups.length; i ++ ) {
+
+		const group = groups[ i ];
+
+		group.start = start;
+		start += group.count;
+
+	}
+
+	// merge groups
+
+	let currentGroup = groups[ 0 ];
+
+	geometry.groups = [ currentGroup ];
+
+	for ( let i = 1; i < groups.length; i ++ ) {
+
+		const group = groups[ i ];
+
+		if ( currentGroup.materialIndex === group.materialIndex ) {
+
+			currentGroup.count += group.count;
+
+		} else {
+
+			currentGroup = group;
+			geometry.groups.push( currentGroup );
+
+		}
+
+	}
+
+	return geometry;
+
+}
+
+
+/**
+ * Modifies the supplied geometry if it is non-indexed, otherwise creates a new,
+ * non-indexed geometry. Returns the geometry with smooth normals everywhere except
+ * faces that meet at an angle greater than the crease angle.
+ *
+ * @param {BufferGeometry} geometry
+ * @param {number} [creaseAngle]
+ * @return {BufferGeometry}
+ */
+function toCreasedNormals( geometry, creaseAngle = Math.PI / 3 /* 60 degrees */ ) {
+
+	const creaseDot = Math.cos( creaseAngle );
+	const hashMultiplier = ( 1 + 1e-10 ) * 1e2;
+
+	// reusable vectors
+	const verts = [ new Vector3(), new Vector3(), new Vector3() ];
+	const tempVec1 = new Vector3();
+	const tempVec2 = new Vector3();
+	const tempNorm = new Vector3();
+	const tempNorm2 = new Vector3();
+
+	// hashes a vector
+	function hashVertex( v ) {
+
+		const x = ~ ~ ( v.x * hashMultiplier );
+		const y = ~ ~ ( v.y * hashMultiplier );
+		const z = ~ ~ ( v.z * hashMultiplier );
+		return `${x},${y},${z}`;
+
+	}
+
+	// BufferGeometry.toNonIndexed() warns if the geometry is non-indexed
+	// and returns the original geometry
+	const resultGeometry = geometry.index ? geometry.toNonIndexed() : geometry;
+	const posAttr = resultGeometry.attributes.position;
+	const vertexMap = {};
+
+	// find all the normals shared by commonly located vertices
+	for ( let i = 0, l = posAttr.count / 3; i < l; i ++ ) {
+
+		const i3 = 3 * i;
+		const a = verts[ 0 ].fromBufferAttribute( posAttr, i3 + 0 );
+		const b = verts[ 1 ].fromBufferAttribute( posAttr, i3 + 1 );
+		const c = verts[ 2 ].fromBufferAttribute( posAttr, i3 + 2 );
+
+		tempVec1.subVectors( c, b );
+		tempVec2.subVectors( a, b );
+
+		// add the normal to the map for all vertices
+		const normal = new Vector3().crossVectors( tempVec1, tempVec2 ).normalize();
+		for ( let n = 0; n < 3; n ++ ) {
+
+			const vert = verts[ n ];
+			const hash = hashVertex( vert );
+			if ( ! ( hash in vertexMap ) ) {
+
+				vertexMap[ hash ] = [];
+
+			}
+
+			vertexMap[ hash ].push( normal );
+
+		}
+
+	}
+
+	// average normals from all vertices that share a common location if they are within the
+	// provided crease threshold
+	const normalArray = new Float32Array( posAttr.count * 3 );
+	const normAttr = new BufferAttribute( normalArray, 3, false );
+	for ( let i = 0, l = posAttr.count / 3; i < l; i ++ ) {
+
+		// get the face normal for this vertex
+		const i3 = 3 * i;
+		const a = verts[ 0 ].fromBufferAttribute( posAttr, i3 + 0 );
+		const b = verts[ 1 ].fromBufferAttribute( posAttr, i3 + 1 );
+		const c = verts[ 2 ].fromBufferAttribute( posAttr, i3 + 2 );
+
+		tempVec1.subVectors( c, b );
+		tempVec2.subVectors( a, b );
+
+		tempNorm.crossVectors( tempVec1, tempVec2 ).normalize();
+
+		// average all normals that meet the threshold and set the normal value
+		for ( let n = 0; n < 3; n ++ ) {
+
+			const vert = verts[ n ];
+			const hash = hashVertex( vert );
+			const otherNormals = vertexMap[ hash ];
+			tempNorm2.set( 0, 0, 0 );
+
+			for ( let k = 0, lk = otherNormals.length; k < lk; k ++ ) {
+
+				const otherNorm = otherNormals[ k ];
+				if ( tempNorm.dot( otherNorm ) > creaseDot ) {
+
+					tempNorm2.add( otherNorm );
+
+				}
+
+			}
+
+			tempNorm2.normalize();
+			normAttr.setXYZ( i3 + n, tempNorm2.x, tempNorm2.y, tempNorm2.z );
+
+		}
+
+	}
+
+	resultGeometry.setAttribute( 'normal', normAttr );
+	return resultGeometry;
+
+}
+
+export {
+	computeMikkTSpaceTangents,
+	mergeGeometries,
+	mergeAttributes,
+	interleaveAttributes,
+	estimateBytesUsed,
+	mergeVertices,
+	toTrianglesDrawMode,
+	computeMorphedAttributes,
+	mergeGroups,
+	toCreasedNormals
+};