The first rotates an object such that if it oriented in the <from>
direction vector then after the rotation it will be oriented in the <to>
direction vector
The first relies in the second.

The second rotates an object around an axis <axis> by the angle <ang>
and was obtained from the src for the function vaxis_rotate (why wasn't
this type of rotation included in POV code) - hope the team don't mind :
)
This calculates a matrix for rotation.

eg cylinder{0,y,.1 lookat(y,<-0.5, 0.23, 0.342>) }
eg cylinder{0,y,.1 translate <0,0.5,.1> axis_rotate(x,45)}

#macro point(from, to)
 #local axis = vcross(from,to);
 #local axis = vnormalize(axis);
 #local ang = acos(vdot(to,from)/vlength(to)/vlength(from));
 axis_rotate(axis, ang)
#end

#macro axis_rotate(axis, ang)
 #local cosx = cos(ang);
 #local sinx = sin(ang);
 matrix<
  axis.x * axis.x + cosx * (1.0 - axis.x * axis.x),
  axis.x * axis.y * (1.0 - cosx) + axis.z * sinx,
  axis.x * axis.z * (1.0 - cosx) - axis.y * sinx,

  axis.x * axis.y * (1.0 - cosx) - axis.z * sinx,
  axis.y * axis.y + cosx * (1.0 - axis.y * axis.y),
  axis.y * axis.z * (1.0 - cosx) + axis.x * sinx,

  axis.x * axis.z * (1.0 - cosx) + axis.y * sinx,
  axis.y * axis.z * (1.0 - cosx) - axis.x * sinx,
  axis.z * axis.z + cosx * (1.0 - axis.z * axis.z),
  0,0,0
 >
#end

Hope these are of some use

Pabs

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