Change this:
    #declare temp_rot = 90 * x * jump_clock;

to this:
    #declare temp_rot = 90 * jump_clock * x;

Maybe that will fix, not easy to understand someone elses code but from
my experience an axis being manipulated must go last.

Josh English wrote:
> 
> I am working on an animation of a chess game, and one of the Knights is
> causing trouble. I want the Knights jump to be rather comical, so it
> gets shorter and fatter, then thins out as it springs up, breaking into
> three component parts, flies through the air and lands again a few
> squares away.
> 
> I had a good jump and made a Quicktime movie out of it which can be seen
> at http://www.spiritone.com/~english/sproing.mov. The bad jump is at
> http://www.spiritone.com/badsproing.mov. When I started to alter the
> shape it moved the piece during the first part of the jump.
> 
> here is the code:
> 
> #declare JumpPoint = a place on the board;
> #declare Target = a nother place n the board
> #declare midPoint = a point on the board directly between target and
> jumpPoint
> #declare roation = rotation value along y axis to align Knight with new
> square
> 
> /// Use 0 to 1 for clock
> 
> #declare anim_clock = clock;
> 
> #declare Trans_1 = 0.25; // stop looking and jump
> #declare Trans_2 = 0.50; // bounce up
> #declare Trans_3 = 0.75; // bounce down
> 
> #switch (anim_clock)
> #range (0,Trans_1) // normalize to target
>    //   rotates the knight to face the direction of the jump
> #break
> 
> #range(Trans_1,Trans_2) // decelerate up
>   // sets to be in normalized range
>   #declare temp_clock = (anim_clock - Trans_1) / (Trans_2 - Trans_1);
>   #declare bounce_time = 3/7;     // transition between prep and jump
> 
> // There are two segments, preparing to jump, and jumping up to the apex
> of
> // the movement
> #switch(temp_clock)
>   #range(0,bounce_time)
>    // create a new normalized clock variable
>     #declare really_temp_clock = temp_clock / bounce_time;
> 
>     #declare squish_value = sin(really_temp_clock * pi * 1.5)/5;
> 
>     #declare newWidth = 1 + squish_value; // get fatter then thinner
>     #declare newHeight =1 - squish_value; // get shorter then taller
> 
>     object { base
>              pigment { rgb 1 }
>              scale <newWidth,newHeight,newWidth>
>              rotate rotation
>              translate JumpPoint }
> 
>     object { body
>              pigment { rgb 1 }
>              scale <newWidth,newHeight,newWidth>
>              rotate rotation
>              translate JumpPoint }
> 
>     object { knight_head
>              pigment { rgb 1 }
>              translate (1.2 - squish_value)*y
>              rotate rotation
>              translate JumpPoint }
> 
>   #break
> 
> #range (bounce_time,1.001)   ////   ***************** The problem is
> here somewhere
>    // create a new normalized clock variable
>     #declare really_temp_clock = (temp_clock - bounce_time) / (1 -
> bounce_time);
> 
>     #declare temp_pos = <0,0,-1>;   // begins to setup the position
>     #declare jump_clock = pow (really_temp_clock,1/2);
>     #declare temp_rot = 90 * x * jump_clock;
> 
>     #declare temp_pos = vrotate(really_temp_clock,temp_rot); // move
> along jump path
>     #declare temp_pos = vrotate(really_temp_clock,rotation);  // rotate
> into position
>     #declare temp_pos = temp_pos + midPoint; // final placement of parts
> 
>     object { base
>              pigment { rgb 1 }
>              rotate really_temp_clock *15*x
>              rotate rotation
>              translate temp_pos }
> 
>     object { body
>              pigment { rgb 1 }
>              rotate really_temp_clock *8*x
>              rotate rotation
>              translate temp_pos * <1,1.25,1> }
> 
>     object { knight_head
>              pigment { rgb 1 }
>              rotate really_temp_clock *-15*x // Nose goes up during
> upward movement
>              translate 1.2*y
>              rotate rotation
>              translate temp_pos * <1,1.75,1> }
>     #break
>   #end
> #break
> 
> #range(Trans_2,Trans_3) // accerlarate down
> 
>   #declare temp_clock = (anim_clock - Trans_2) / (Trans_3 - Trans_2);
> 
>   #render concat ("Temp Clock is ",str(temp_clock,3,3))
>   #declare temp_pos = <0,0,-1>;
>   #declare temp_clock = pow (temp_clock,2);
>   #declare temp_rot = ((90*temp_clock)+90)*x;
> 
>   #declare temp_pos = vrotate(temp_pos,temp_rot);
>   #declare temp_pos = vrotate(temp_pos,rotation);
>   #declare temp_pos = temp_pos + midPoint;
> 
>   object { base pigment { rgb 1 }
>            rotate (15-(temp_clock*15))*x
>            rotate rotation
>            translate temp_pos }
> 
>   object { body pigment { rgb 1 }
>            rotate (8-(temp_clock*8))*x
>            rotate rotation
>            translate temp_pos * <1,1.25,1> }
> 
>   object { knight_head
>            pigment { rgb 1 }
>            rotate (-15+(temp_clock*15))*x
>            translate 1.2*y
>            rotate rotation
>            translate temp_pos * <1,1.75,1> }
> 
> #break
> 
> #range (Trans_3,1.01) // normalize to target
> 
>  // rotate back
> 
> #break
> #end
>
-----------------------------------------------------------------------------------------------------------
> 
> Now, during the second part of the second segment, is where the problem
> lies. It starts the jumpat the midpoint and behaves as if it's rotating
> around the target position, then during the third segment, it appears
> above the midpoint and rotates around the midpoint down to the target.
> The code is exactly the same except that I add 90 degrees to the
> rotation. This code also did not change from the successful version
> except in the following ways: since I broke the second segment up  with
> a second #switch statement, I created the really_temp_clock variable and
> used that instead of temp_clock in the first part of that bit of code.
> This is the confusing part, and I'm asking if anyone can see the
> mistake, since I can't.
> 
> Thanks for any aide.
> 
> Josh English
> eng### [at] spiritonecom
> http://www.spiritone.com/~english

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
=Bob

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