Bugfix: The binary STL exporter didn't handle meshes imported from binary STL files (BufferGeometry)

examples/js/exporters/STLBinaryExporter.js

@@ -17,11 +17,29 @@ THREE.STLBinaryExporter.prototype = {
 
 		return function parse( scene ) {
 
+			// We collect objects first, as we may need to convert from BufferGeometry to Geometry
+			var objects = [];
 			var triangles = 0;
 			scene.traverse( function ( object ) {
 
 				if ( ! ( object instanceof THREE.Mesh ) ) return;
-				triangles += object.geometry.faces.length;
+
+				var geometry = object.geometry;
+				if ( geometry instanceof THREE.BufferGeometry ) {
+
+					geometry = new THREE.Geometry().fromBufferGeometry( geometry );
+
+				}
+
+				if ( ! ( geometry instanceof THREE.Geometry ) ) return;
+				triangles += geometry.faces.length;
+
+				objects.push( {
+
+					geometry: geometry,
+					matrix: object.matrixWorld
+
+				} );
 
 			} );
 
@@ -31,25 +49,13 @@ THREE.STLBinaryExporter.prototype = {
 			var output = new DataView( arrayBuffer );
 			output.setUint32( offset, triangles, true ); offset += 4;
 
-			scene.traverse( function ( object ) {
-
-				if ( ! ( object instanceof THREE.Mesh ) ) return;
-
-				var geometry = object.geometry;
-				if ( geometry instanceof THREE.BufferGeometry ) {
-                            
-					geometry = new THREE.Geometry().fromBufferGeometry( geometry );
-                            
-				}
-
-				if ( ! ( geometry instanceof THREE.Geometry ) ) return;
-
-				var matrixWorld = object.matrixWorld;
+			// Traversing our collected objects
+			objects.forEach( function ( object ) {
 
-				var vertices = geometry.vertices;
-				var faces = geometry.faces;
+				var vertices = object.geometry.vertices;
+				var faces = object.geometry.faces;
 
-				normalMatrixWorld.getNormalMatrix( matrixWorld );
+				normalMatrixWorld.getNormalMatrix( object.matrix );
 
 				for ( var i = 0, l = faces.length; i < l; i ++ ) {
 
@@ -65,7 +71,7 @@ THREE.STLBinaryExporter.prototype = {
 
 					for ( var j = 0; j < 3; j ++ ) {
 
-						vector.copy( vertices[ indices[ j ] ] ).applyMatrix4( matrixWorld );
+						vector.copy( vertices[ indices[ j ] ] ).applyMatrix4( object.matrix );
 
 						output.setFloat32( offset, vector.x, true ); offset += 4; // vertices
 						output.setFloat32( offset, vector.y, true ); offset += 4;