computeBoundingSphere() {

		if ( this.boundingSphere === null ) {

			this.boundingSphere = new Sphere();

		}

		const position = this.attributes.position;
		const morphAttributesPosition = this.morphAttributes.position;

		if ( position && position.isGLBufferAttribute ) {

			console.error( 'THREE.BufferGeometry.computeBoundingSphere(): GLBufferAttribute requires a manual bounding sphere.', this );

			this.boundingSphere.set( new Vector3(), Infinity );

			return;

		}

		if ( position ) {

			// first, find the center of the bounding sphere

			const center = this.boundingSphere.center;

			_box$2.setFromBufferAttribute( position );

			// process morph attributes if present

			if ( morphAttributesPosition ) {

				for ( let i = 0, il = morphAttributesPosition.length; i < il; i ++ ) {

					const morphAttribute = morphAttributesPosition[ i ];
					_boxMorphTargets.setFromBufferAttribute( morphAttribute );

					if ( this.morphTargetsRelative ) {

						_vector$8.addVectors( _box$2.min, _boxMorphTargets.min );
						_box$2.expandByPoint( _vector$8 );

						_vector$8.addVectors( _box$2.max, _boxMorphTargets.max );
						_box$2.expandByPoint( _vector$8 );

					} else {

						_box$2.expandByPoint( _boxMorphTargets.min );
						_box$2.expandByPoint( _boxMorphTargets.max );

					}

				}

			}

			_box$2.getCenter( center );

			// second, try to find a boundingSphere with a radius smaller than the
			// boundingSphere of the boundingBox: sqrt(3) smaller in the best case

			let maxRadiusSq = 0;

			for ( let i = 0, il = position.count; i < il; i ++ ) {

				_vector$8.fromBufferAttribute( position, i );

				maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( _vector$8 ) );

			}

			// process morph attributes if present

			if ( morphAttributesPosition ) {

				for ( let i = 0, il = morphAttributesPosition.length; i < il; i ++ ) {

					const morphAttribute = morphAttributesPosition[ i ];
					const morphTargetsRelative = this.morphTargetsRelative;

					for ( let j = 0, jl = morphAttribute.count; j < jl; j ++ ) {

						_vector$8.fromBufferAttribute( morphAttribute, j );

						if ( morphTargetsRelative ) {

							_offset.fromBufferAttribute( position, j );
							_vector$8.add( _offset );

						}

						maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( _vector$8 ) );

					}

				}

			}

			this.boundingSphere.radius = Math.sqrt( maxRadiusSq );

			if ( isNaN( this.boundingSphere.radius ) ) {

				console.error( 'THREE.BufferGeometry.computeBoundingSphere(): Computed radius is NaN. The "position" attribute is likely to have NaN values.', this );

			}

		}

	}
Computes the bounding sphere of the geometry, and updates the `boundingSphere` member.
The engine automatically computes the bounding sphere when it is needed, e.g., for ray casting or view frustum culling.
You may need to recompute the bounding sphere if the geometry vertices are modified.