Geometry Playground

Geometry Playground is a free ruler and compass Java application for multiple geometries. (You will need Java 1.50 or greater to run it.) Positive comments and praise should be sent to Daniel (deej) Heath. Complaints, criticism, flames and bug reports should be sent to Joshua Jacobs. You will need to replace the -A.T- in either email address with the "at" symbol (sorry for the inconvenience -- this protects us from spam). To start Geometry Playground, follow the link below.

Although most features of Geometry Playground are self-explanatory, there are now some short tutorial videos that might help explain a few of the more obscure features. They are:

1. Playground1, constructing and moving segments in Euclidean geometry.
2. Playground2, more constructions, this time in spherical geometry.
3. Playground3, measuring distances, areas, etc., and their sums, ratios, etc..
4. Playground4, display options: playing with labels, models, and scale.
5. Playground5, opening and saving files, undoing, and fixing objects.

There is an editable wiki, which includes hands-on discovery activities. Do you want activities for your geometry class? Find some at the wiki. Do you want to make adjustments or additions to the curricula? Do so at the wiki. The code is also open source, so that you can add to or edit that as well. Contact Josh if you wish to do so. There are some constructions saved in a .zip file, including some traditional Euclidean constructions and their counterparts in other geometries. Follow this link to download those constructions.

Do you want Geometry Playground to be offered in your language? Download Playground Messages, translate it, and send it to deej. Note that "(your language)" should be translated into the word for your language in your language. For example, in English, that line reads: "languageText = English".

For Geometry Playground connoisseurs we have added a few technical tools, all of which are showcased in files PlaygroundExample.jnlp and PlaygroundExample.hyp.

• Fixed points, points that cannot move with respect to one another, can be created by changing the type of a POINT in a saved file to FIXedPT.
• Constants can be created by changing the type of a POINT in a saved file to CONSTANT, and replacing the z-coordinate with the value of the constant.
• A display string (without commas) can be added to any measure (including CONSTANTs) by simply adding a comma followed by the display string at the end of the line in the saved file.
• Arguments can be passed to Geometry Playground through the .jnlp file.
  • The first argument should be the URL of a saved construction, beginning with http://. When Geometry Playground finds a valid URL in the first argument, it attempts to begin by loading that construction in the appropriate geometry.
  • A second argument may contain a 0, 1, 2, or 3; if valid, Geometry Playground will automatically switch to that model of the current geometry. For example, in spherical geometry, 0=sphere model, 1=plane model, 2=Mercator model, and 3=invalid (so the default model [0] would be chosen).