Forum: Poser - OFFICIAL


Subject: Problem with Poser Confusing X and Y axis rotations

pookah69 opened this issue on May 23, 2003 ยท 26 posts


BeatYourSoul posted Tue, 27 May 2003 at 2:03 PM

Yes, Poser DOES. This is a standard, well-known problem with Euler Angles. It is unavoidable when using Euler Angles. They couldn't have coded for it. They could have used Quaternions instead, only showing Euler Angles for the user's edification. Quaternions are a known way to avoid gimbal lock, although still not perfect. It happens in 3DSMax (though they supposedly have a "workaround" but haven't heard much about its success). It happens in LightWave (try rotating the perspective view to coincide with the Y-axis and watch your view lock to it). It happens in many 3D applications, any using Euler Angles. The way to avoid it is as was discussed: parenting so that one parent acts as an X rotator and another acts as Y rotator. In all cases, you must avoid gimbal lock on the parent(s), or you're back where you started. Sorry, the reason is VERY important since it is a fundamental mathematical one, not one restricted to your precious Poser application. If any of you would bother to learn about the technical side of 3D mathematics and its use in computer programs, you'd be better equipped to avoid these problems or understand them when they occur. BYS - 3D CG User: Poser 4/ProPack, Poser 5, Cinema 4D XL 7.3, Cinema 4D XL R8, BodyPaint3D, ImageModeler 3.5, LightWave 7.5 3D, Maya 4.5 PLE, UV Mapper, AutoCAD 2000. - 3D Programmer: C/C++/Java/Java 3D/VRML for 10 years (15 years programming generally) - 3D Books: Computer Graphics - Foley et al 3D Computer Graphics - Watt Graphics Gems I - IV Black Art of 3D Game Programming - LaMothe High-Resolution Computer Graphics Using C - Angell Computer Graphics for Java Programming - Ammeraal Java 3D API Jump-Start Computer Graphics - Plastock & Kalley Computer Graphics Handbook - Mortenson Warping and Morphing of Graphical Objects - Gomes et al The Annotated VRLM 2.0 Reference Manual - Carey & Bell ...plus various mathematics books on Vector and Tensor Analysis, Chaos, Calculus, Algrebra, Geometry, Analytic Geometry, Topology, Matrix Theory (don't need one for Trig as I'm well versed in it). ...plus several dozen minor 3D and 3D programming books since sold. Knowledge is Power...