Alright, I found a method that gives the transform based on the alpha value, so I've figured that part of it out. However, is there some access in Java to get the spline equations (I need first and second derivatives at various points on the splines)?
If not, I assume they must be calculated manually...but after reading the K-B Cubic Spline document, it appears that the equations will not work correctly for the first and last spline segment. Any clarifications out there? Sorry to keep this going. Thanks, Nick I've read the kochbart.pdf link that you've sent, and it was quite helpful in understanding the math behind the interpolator. However, I see a method in the KBSplinePathInterpolator class called computePathInterpolation, but it is a protected method. It seems like it is something like this that I would want to have access to in order to find many discrete points along the spline path so that I could draw a polyline approximating the spline. I'm still not able to see how to get at either the actual points lying along the spline's path or how to get the equations of the spline in some parametric form so that I can calculate these points myself. Thanks, Nick Yes, unfortunately we must one's own to find how this work. Let's see API: "RotPosScaleTCBSplinePathInterpolator behavior. This class defines a behavior that varies the rotational, translational, and scale components of its target TransformGroup by using the Kochanek-Bartels cubic spline interpolation to interpolate among a series of key frames (using the value generated by the specified Alpha object). The interpolated position, orientation, and scale are used to generate a transform in the local coordinate system of this interpolator." All Java3D spline interpolators based on Kochanek-Bartels cubic spline mathematics. I found this usefull information about Kochanek-Bartels cubic spline: http://www.cubic.org/~submissive/sourcerer/hermite.htm http://www.magic-software.com/Documentation/kochbart.pdf Probably are other sources... To understand how this work read above links information then see inside source of RotPosScaleTCBSplinePathInterpolator. Onse I rewrite RotPosScaleTCBSplinePathInterpolator and attendant classes for my needs. Vladimir A. Vernikovski Programmer ------------------------------------------- JPROOF Technologies Ltd. ----- Original Message ----- From: "Nick Stark" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, June 04, 2003 6:59 PM Subject: Re: [JAVA3D] 3D Cubic Splines > Yeah, these were the spline classes I was referring to in my email. I read > through the API documentation, but there is very little explanation of the > variables in the KeyFrames. So it's quite difficult to understand how to > construct one of these spline interpolators. If someone has some sample > code using any of these objects, I'd love to take a look at it to get some > understanding of what's going on. > > Thanks again, > Nick > > > > Hi! > In Java3D is some interpolators for spline animation: > KBRotPosScaleSplinePathInterpolator > KBSplinePathInterpolator > RotPosScaleTCBSplinePathInterpolator > TCBSplinePathInterpolator > > Try to use. Read API documentation. Those realy work! > > Vladimir A. Vernikovski > Programmer > ------------------------------------------- > JPROOF Technologies Ltd. > ----- Original Message ----- > From: "Nick Stark" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Wednesday, June 04, 2003 6:42 PM > Subject: [JAVA3D] 3D Cubic Splines =========================================================================== 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". =========================================================================== 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".
