Loading Models UCM3 models are a collection of individual files that store various pieces of information that UCMViewer 3 needs to display the model. When you extract an UCM3 model from a ZIP archive after downloading, please make sure that you keep the directory tree intact and ensure that the files remain together. The File>Open Model menu item will load the first page of the selected UCM3 model. Once loaded, you can navigate through the rest of the model's pages using the Prev/Next buttons or the page drop-down list. In addition to the page navigation buttons and drop-down list, two zoom buttons and a zoom level drop-down list are provided for further manipulation of the document. Immediately to the right of these buttons are the Pan/Drag tool and the Region Inspector tool. The Pan/Drag tool allows you to drag the model canvas around in the preview using your mouse, and the Region Inspector tool allows you to click on a point anywhere on the canvas and find out what color region it belongs to.