Peter Alfeld, --- Department of Mathematics, --- College of Science --- University of Utah

User Guide to Polygon Viewer

I wrote this simple polygon viewer to have one that I understand completely and that I can easily use and modify in the design of my applets. Its most significant disadvantage is that it is slow compared to some others that are available, and very slow compared to commercial software (like Explorer) that is available on particular hardware platforms. It also flickers more than I would like.

Presumably you came here since you were using the viewer on some other page, and you need the documentation. However, clicking on the cube nearby will bring up a window that you can use to try out the things you'll read about on this page. We'll refer to it as the Display Window and call whatever is displayed in it the object.

Rotating the Image

The basic operation is a rotation of the object which generates the three-dimensional effect. Think of the object you are viewing as being contained in a transparent sphere. Move the cursor to a point in the image, depress the mouse button, and keep it down. That attaches the cursor to the sphere. Then drag the mouse, with the mouse button still depressed. The sphere, and therefore the object, will rotate. To save computer time, and make the interaction a little more nimble, during the rotation the polygons are displayed as outlines only. As soon as you release the mouse button the object is displayed as before. Try it now!

Secondary modes can be obtained by selecting certain menu items or pressing the corresponding keys, as indicated below. In all cases the viewer reverts to the rotation mode automatically. So if for example you want to zoom twice you have to reselect the zoom mode after zooming the first time.

The Menus

There are two menus, the Mode Menu, and the Color Menu. All menu items have equivalent key strokes, and eventually you will probably find the key strokes more convenient than the menus. Most Menu items toggle features (i.e., turn them on and off).

The Mode Menu

The Color Menu

Resizing the Display Window.

You can resize the display window (like any window on your particular system) and the drawing of the object should automatically adjust itself to the new window. It's likely that the larger the window the slower the interaction with the object will be.

Known Bugs/Things to do.


Go to Peter Alfeld's Home Page.

Designed for netscape.