The applet on this page can interpolate between two polygons and represent the interpolation as a wireframe, where each triangle of two gray lines and one black line represents a moving line segment.
Draw the first snapshot in the applet window below by clicking at the points that the polygon should contain. The applet shows the part of the polygon that you have already drawn. The polygon must be drawn in clockwise order.
When the first snapshot is complete, click on the Store snapshot button. This automatically adds the line that closes the polygon. The first snapshot is then displayed in red. Then you can draw the second snapshot in the same way. When you click the Store snapshot button after drawing the second snapshot, the applet will create an interpolation between the two snapshots and display this as a wireframe where the first snapshot is drawn in red, the second in blue, and the lines between them are drawn in gray.
After you have looked at the interpolation, you may click on the Draw button to draw another set of snapshots. You can, in fact, use this button at any time to reset the applet, so that if you make a mistake in drawing the snapshot, you may start over.
Note: The interpolation algorithm will not work on polygons with intersecting lines or with polygons where two or more points have the same location.
There is also a downloadable application version of this applet. This version of the program can create a VRML file that represents the moving cycle. To do this, write the name of the file into the text field provided and press Enter. The application is installed by unpacking the zip-file in whichever directory you want it to be. You may run it by writing "java MCInterpolator" on the command line. It requires Java version 1.2 or later.
Some documentation of the algorithms behind the applet can be found here.
The source code for the application version can be found here. This code contains the javadoc comments that were used to create the documentation. This code may be compiled by running "javac MCInterpolator.java" on the command line in the directory where the file MCInterpolator.java is.
Polygons must be drawn in clockwise order. The last segment is added automatically.