I've reported this problem maybe 8 or 9 (or more) months ago. (And it is a problem. It caused me a problem and now its caused at least one other person a problem. Unfortunately, its not a bug.) At that time, there was mention of the normalization in the documentation, some place.
But I still feel this is wrong headed. To me, normalizing quaternions is like normalizing vectors: sometimes you want to and other time you don't. I would think it would be such a simple change that the Java 3D folks could remove the normalization from the quaternion constructor in under 5 minutes. If you want a normalized quaternion you would use the normalize() method, just like you do for vectors. That's my 2 cents. Bob Gray -----Original Message----- From: Discussion list for Java 3D API [mailto:[EMAIL PROTECTED]]On Behalf Of Fred Klingener Sent: Friday, March 01, 2002 11:01 AM To: [EMAIL PROTECTED] Subject: Re: [JAVA3D] quaternion bug/feature? From: "St�le Pedersen" <[EMAIL PROTECTED]> Sent: Friday, March 01, 2002 9:53 AM > hi, after using quaternions (javax.vecmath.Quat4f) i noticed that the > constructor Quat4f(float x, float y, float z, float w) not just set > these parameters as values, it also normalize the object. > It doesnt say anything about this in the javadoc. > Maybe this is a feature, i dont know, i hope this is a bug, if not, > please let people know that the object is normalized. > i attach a small program to illustrate the problem. vecmath constructors normalize quaternions - one of the little details left endearingly out of the docs. I haven't experimented with the returns of other quat methods, but I suspect some others will enforce the normalization too. If you want to use quaternions to do things other than spherical rotations, you have to roll your own. You can try to override the normalization with Tuple sets, but that's just asking for more trouble IMHO. My winter project is building a dual number package on top of vecmath that includes general quaternion and dual quaternion math, but it's far from even an alpha. And there are only three more weeks of winter. hth, Fred Klingener Brock Engineering =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff JAVA3D-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help". =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff JAVA3D-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
