You can adjust the view in the ST-Viewer geometry window using the mouse and toolbar buttons.
Initially, the geometry window is in Rotate mode, and you can rotate the view by dragging the mouse in the window while holding down the left mouse button. Clicking Pan toolbar button changes the behavior so that dragging slides the viewpoint from side to side. The button for the active mode is highlighted on the toolbar, and the cursor in the window will also match the mode icon. The other modes on the toolbar are for selecting shapes, faces, or edges.
Zoom in to see details on the geometry by clicking on the Zoom In button or by typing Ctl-Up. Zoom out to see more of the geometry by clicking on the Zoom Out button or by typing Ctl-Down. The Zoom All button adjusts the view position and zoom level so that the entire part is centered and fits in the window.
The toolbar also has a list predefined views, so that you can quickly align the geometry display to coordinate axes. The Top and Bottom buttons align the display to the Z axis. The Front and Back buttons align the display to the X axis. The Left and Right buttons align the display to the Y axis. Finally, the Isometric button aligns the view so that the angle between the projection of any two of the coordinate axes is drawn as 120°
On the View menu, you can choose whether you would like the geometry to be displayed using a Perspective or Orthographic drawing style. With the perspective drawing style, parallel lines appear to converge in the distance, while in an orthographic style, they remain parallel. The orthographic style makes it easier to visually compare the size of things at different distances from your viewing location.