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the views on the left are 3 orthographical cameras installed in the scene according to the selected box. keys 5/6/7 to show/hide the installed camera frames.
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we use rear-view, other than front-view, so that when we adjust the position of box, this view moves in the same direction as the top-down view, otherwise it would be very confusing (imagine the box in the first view moves right but in the second view moves left.)
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the main view is a perspective camera by default.