function buildPlane( u, v, w, udir, vdir, width, height, depth, gridX, gridY, materialIndex ) {

			const segmentWidth = width / gridX;
			const segmentHeight = height / gridY;

			const widthHalf = width / 2;
			const heightHalf = height / 2;
			const depthHalf = depth / 2;

			const gridX1 = gridX + 1;
			const gridY1 = gridY + 1;

			let vertexCounter = 0;
			let groupCount = 0;

			const vector = new Vector3();

			// generate vertices, normals and uvs

			for ( let iy = 0; iy < gridY1; iy ++ ) {

				const y = iy * segmentHeight - heightHalf;

				for ( let ix = 0; ix < gridX1; ix ++ ) {

					const x = ix * segmentWidth - widthHalf;

					// set values to correct vector component

					vector[ u ] = x * udir;
					vector[ v ] = y * vdir;
					vector[ w ] = depthHalf;

					// now apply vector to vertex buffer

					vertices.push( vector.x, vector.y, vector.z );

					// set values to correct vector component

					vector[ u ] = 0;
					vector[ v ] = 0;
					vector[ w ] = depth > 0 ? 1 : -1;

					// now apply vector to normal buffer

					normals.push( vector.x, vector.y, vector.z );

					// uvs

					uvs.push( ix / gridX );
					uvs.push( 1 - ( iy / gridY ) );

					// counters

					vertexCounter += 1;

				}

			}

			// indices

			// 1. you need three indices to draw a single face
			// 2. a single segment consists of two faces
			// 3. so we need to generate six (2*3) indices per segment

			for ( let iy = 0; iy < gridY; iy ++ ) {

				for ( let ix = 0; ix < gridX; ix ++ ) {

					const a = numberOfVertices + ix + gridX1 * iy;
					const b = numberOfVertices + ix + gridX1 * ( iy + 1 );
					const c = numberOfVertices + ( ix + 1 ) + gridX1 * ( iy + 1 );
					const d = numberOfVertices + ( ix + 1 ) + gridX1 * iy;

					// faces

					indices.push( a, b, d );
					indices.push( b, c, d );

					// increase counter

					groupCount += 6;

				}

			}

			// add a group to the geometry. this will ensure multi material support

			scope.addGroup( groupStart, groupCount, materialIndex );

			// calculate new start value for groups

			groupStart += groupCount;

			// update total number of vertices

			numberOfVertices += vertexCounter;

		}
Holds the constructor parameters that have been
used to generate the geometry. Any modification
after instantiation does not change the geometry.

@type {Object}