ZofzPCB is described as 'The fastest, easiest, most intuitive way to check your PCB design… before it goes to manufacturing With ZofzPCB you get: -Realistic 3D rendering from your Gerber files that shows you just how your finished board will look and unveils errors that are difficult to detect in a 2D' and is an app in the Education & Reference category. There are five alternatives to ZofzPCB for Mac, Windows, Linux and Online / Web-based. The best alternative is Gerbv, which is both free and Open Source. Other great apps like ZofzPCB are Cuprum (Freemium), 3D Gerber Viewer (Free), MCN Gerber Viewer (Free) and ViewMate (Freemium).
Simple Gerber viewer for the OS X platform. It runs on OS X 10.10 (Yosemite) and 10.11 (El Capitan). There are two versions: Full and Community Edition. The (paid) Full version contains fully functional versions of the latest and greatest features.