VPNBody: Getting Started


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Downloads

You must have the Python interpreter and the VPython libraries installed on your computer. Visit http://www.vpython.org and click on "Downloads." Follow the instructions.

Next, download VPNBody 2.1 in the zipped archive. Unzip the files to your hard drive. (Follow this link for more information about the zipped archive.)

Run the Program

Navigate the directory where you unzipped the VPNBody files. Double-click on the file vpnb.py.

The VPNBody directory

You should see the following screen:

VPNBody filename prompt

At the prompt, type "InnerPlanets.txt" (without the quotes), and hit enter. Do not close this window!

The animation window will appear next:

VPNBody click to begin

Click anywhere in the animation window to start the simulation. You will see this:

VPNBody animaiton

The elapsed time appears in the bottom left corner, and the relative energy error  appears in the bottom right-hand corner.

You can pause and restart the animation using the left-mouse key. Using the right-mouse key you can rotate the field of view:

VPNBody rotated view

You can zoom in and out using both mouse keys and moving the mouse forward to zoom in and backward to zoom out:

VPNBody zoom