"Nicolas Alvarez" <nic### [at] hotmailcom> wrote:
> Why not using splines?
>
>

> news:web.40a4ebc89de6780ab2365a790@news.povray.org...
> > I actually work on a bigger project, showing a gothic cathedral. I am
> > planning a cam-flight from far away toward and round the building, later a
> > walkthrough inside the building (90-120 secs).
> > For animating the cam-track, I was not very happy whith the implemented
> > POV-animating possibilties.
> > I used POV-Ray many years and even under DOS I did a lot of scene scripting
> > by using external script-generating tools. First POV-vrersions had no
> > #macro, so I scripted some tools, generating from a text file whith mixed
> > POV- and Expression-code complete POV-scene files. Since I am using
> > UNIX-System my possibilities got a lot better, especially using perl:-)
> > Back to animation: to creat my cam-track, i make a simple text file, where
> > all relevant cam-options are listed in keyframes e.g. like this:
> >
> > frame distance<0,0,0>   height  rotation  look_at_x  look_at_y look_at_z
> > 0000        500           200      0          0           23       0
> > 0200        200           100      45         0           23       0
> >
> > For my current project for each keyframe I declare about 26 options
> > including cam-angle(for Zooming and wide-angle), focalblur, fog, lights as
> > dynamical options.
> >
> > This KEY.INC-file runs through a perl-process which generates a
> > POV-include-file for each frame of the animation by interpolating curves
> > through the given control points in the keyframes. After the
> > POV-Include-file is generated for a frame (or a set of frames), these
> > frame(s) are rendered and attached to the animation. All these processes
> > are managed by one perl script and can be stopped, continued or changes can
> > be made to the cam-track whithout losing all rendered data.
> > At the moment, this wroks only with global keyframes, but I am working on
> > the implementation of the possibility to key each single option on
> > different frames.
> > Also I'm working on the possibility to change the orientation of the cam
> > between global look_at-mode and relative rotate_xyz-mode to the actual
> > moving vector of the cam.
> >
> > Anyone tried this or something similar?
> > Coments welcome ...
> > Siggi
> >
> >
> >
I've tried it with splines, but if your moving options get more than only
position and rotation (for Cam Pos and look_at) and the pathes got longer
and have more than 10 control points, splines have the tendency to
interpolate not accurate enough e.g to set a proper path of the cam between
columns of a building. The other point is, that if you change a single
sequence of a spline, it can change the whole curve. Defining each sequence
separate avoids this.
Third, if I define the cam-position path not as one single 3D-curve, but as
three curves for height, distance from <0,0,0> and Y-rotation gives me the
opinion, that the cam moves slightly around my building (Y-rotation &
distance are constant curves) while the cam is moving up and down even with
hard changes in the movement.

Regards Siggi

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