Update viewer.js

viewer.js

@@ -133,6 +133,16 @@ export async function initializeViewer(config, instanceId) {
   app.setCanvasFillMode(pc.FILLMODE_NONE);
   app.setCanvasResolution(pc.RESOLUTION_AUTO);
 
+  const containerHandler = app.loader.getHandler('container');
+  containerHandler.pcMaterialOptions = {
+      processTransmission: true,
+      processVolume: true,
+      processIOR: true,
+      processSheen: true,
+      processClearCoat: true,
+      processVariants: true
+  };
+
   resizeObserver = new ResizeObserver(entries => {
     entries.forEach(entry => {
       app.resizeCanvas(entry.contentRect.width, entry.contentRect.height);