Rotating animations

*To*: mathgroup at smc.vnet.net*Subject*: [mg2559] Rotating animations*From*: rustybel at foothill.net (Russell Towle)*Date*: Mon, 20 Nov 1995 01:15:05 -0500

I have constructed hundreds of animations using Mathematica 2.2 on a Mac platform with 68 megabytes of RAM. I can assure of this: 1. The built-in function SpinShow yields erratic results, generating points-of-view too close to the 3D object(s), and handles the optional Euler angles in a strange way. 2. The option, SphericalRegion->True, as cited by those whose replies have been posted, is not a guarantee that one will construct animations which do not "wobble" or change size, although the image area does remain uniform, or nearly so. 3. Although the other loop structures like Table may be used, I find Do loops more intuitively obvious. The functions RotateShape and TranslateShape, hidden within Graphics Shapes, are very useful tools for both static drawings and animations. The only way I have ever been able to ensure that both the 3D object(s) and their viewing area remain absolutely stable is to use PlotRange as an option of Show, inside a Do loop. The iterator can be used to govern rotation and translation, within Show. This approach will smoothly represent the apparent change in size of 3D objects as they move closer and farther away from a fixed ViewPoint, but it will absolutely prevent their unwanted, spurious changes in size, which results even when SphericalRegion->True is invoked. I realize that my previous comment was rather long. So is this one. But, since I find Mathematica to be a rather wonderful program, and especially enjoy the animation capabilities of Mathematica, I am sorry to find that users are having problems with constructing animations. Russell Towle Box 141 Dutch Flat, CA 95714 USA