Nieminen Mika wrote:
> 
> Lewis Sellers <lse### [at] usitnet> wrote:
> : //example
> : #declare cam_l = <.6,5.4,16>;
> : #declare cam_lat =  <15,1,24>;
> 
>   Location and look_at... ok, but what about angle, sky and right?
>   The right vector is not usually changed during an animation, but the
> sky vector is very usually changed and also the angle (see the most probably
> winner animation "the pool shark" at irtc :) ).

I was the one who helped Lewis out on his project; the code I use
presumes a constant angle, but can easily be adjusted for a changing
angle (simply alter the z-value of the text offset).  "Sky" usually
does not change during an animation (it is either constantly y or z),
but up and right do; they are determined by vector maths based on the
location, look_at, and sky values.  In any event, the code I use
calculates all of these vectors before they are fed to the
transformation matrix.

I have an animation of an approach to a rotating space ship; the
camera goes from being oriented straight up to following the rotation
of the ship (so that the stars appear to spin); the timer in the lower
corner of the view is placed with this code, and is rock-steady for the
whole animation.  The fades I used in my IRTC entry are done with
polygons placed before the camera; I didn't have to fiddle with their
placement, because I could just place them relative to the camera, and
use the matrix to put them where they needed to be.  The subtitle in
the animation uses the same technique, as does the lettering in the
poster.

Regards,
John

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