WEBSITE AND WEBSITE GRAPHICS CREATED WITH XARA DESIGNER 6 PRO Because the rings are rotating around a common axis, the first and last rings are lined up adjacent to each other, with the front of the first ring lined up against the back of the last ring, and even a tiny error shows up as a visible gap or lip. So not only did the sizing pixels have to be accurately positioned, the ring centres had to be very carefully aligned onto the sizing pixel’s mutual centre. Using Xara Xtreme’s Guide lines and rotation centres of the shapes at extreme magnification made this pretty easy to do. This was a lot of effort just to be able to use 150 rings. So, was it worth it? 2010 Mike Sims Spinning the Hollow Earth - Animation Xara 3D has animation tools, but there is a limitation; only one animation type can be used at any one time. So since I used the Swing animation in the Hollow Earth to move the rings into position, I no longer can use the Rotate animation to spin it, and still keep it as a globe. This is more an inconvenience than anything else, because it is still perfectly possible to spin the Hollow Earth, it just has to be done manually. This is done by changing the viewpoint in Xara 3D and taking a screen shot, placing it into an animation frame in Xara Xtreme, then advancing the viewpoint a set number of degrees and repeating the cycle, building up the required series of such frames. When done, each frame can be cropped, and an animated GIF can be exported. More frames means more work and a larger file size, but also smoother animation. I bit the bullet to create the smoothest animation with a full 360 frames, with a viewpoint shift of 1° per frame. Xara 3D doesn’t let you change the viewpoint less than 1 degree at a time (thank goodness!). But once I have the all these frames in Xara Xtreme, and the file saved, I can export the full 360 frames, or delete every second frame and export 180 frames, or delete every 2nd, 3rd and 4th frame, and export 90 frames, and so on. Partial Swing Angles One last little detail, and we are done. With 150 rings to be swung, the required Swing angle is 2.4° for the 2nd ring, 4.8° for the next, and so on. Unfortunately, Swing doesn’t let you set fractional degrees, so I could set 2° or 3° but not 2.4°. With 2° increments, there would be a gap because the rings wouldn’t swing enough to reach all the way around the equator, and with 3° increments, the last several rings would overshoot beyond the first few rings. I got round this by not letting Swing run to its maximum extent, but I needed to pinpoint which frame to pause on. As the Swing animation runs, it starts off with no Swing, then the rings start spreading out around the equator in one direction, slowing down as they approach maximum swing at frame 64, then reversing back to no Swing at frame 128 and carrying on in the reverse direction around the equator to hit the opposite maximum at frame 196, and then returning to no Swing at frame 256. By measuring the amount of Swing of a single line against a calibrated background, I identified frame 39 as being 80% of full Swing.  I could set the Swing angles in 3° increments, and by pausing the animation at frame 39, the rings only achieve 80% of their potential maximum. 80% of 3°= 2.4°. Thus the rings close properly when the animation is paused on frame 39 of 256. And thank goodness, it was so! I hope you enjoyed this account of the Making of the Hollow Earth, and found useful tidbits of information in it. Click here to see a larger version of the animation. The file is about 5MB so be patient. It takes a minute to download and play. Mike Sims Send e-mail H    1    2    3    4    5    6    Download Zipped Tutorial