• Adobe After Effects Expressions

  Magic Z-Rotation

  Posted by Sebastian Martinez on August 15, 2008 at 11:05 am

  Hi everyone!
  I’m not a great scripter at all but this forum help me a lot to fix a lot of problems and broadened the possibilities in AE! So thank you Dan, Filip and all the others! I’ll keep on watching …

  There’s still a problem I have allready posted before, but couldn’t be answered for my own reasons.

  An auto-orient camera is flying around 360° in 3D space. How can I manipulate the Z-Rotaion of the camera that it stays straight with the “absolut” Z-vector of the space? Otherwise the the Z has to be adjusted brute force – tedious and stupid looking.

  So I tried it with this for the Z-Rotaion, a tweak of Dan Ebberts Expression to orient objects towards cameras. ‘Null 1‘s position is pickwipped to the camera’s viewpiont to get the “absolute” Z-vector for the camera. Didn’t work though:

  L = thisComp.layer(“Null 1”);
  s = L.scale/100;
  u = L.toWorldVec([s[0],0,0]);
  v = L.toWorldVec([0,s[1],0]);
  w = L.toWorldVec([0,0,s[2]]);
  sinb = clamp(w[0],-1,1);
  b = Math.asin(sinb/thisComp.pixelAspect);
  cosb = Math.cos(b);
  if (Math.abs(cosb) > .0005){
  c = -Math.atan2(v[0],u[0]);
  a = -Math.atan2(w[1],w[2]);
  }else{
  a = Math.atan2(u[1],v[1]);
  c = 0;
  }
  [radiansToDegrees(a),radiansToDegrees(b),radiansToDegrees(c)]

  Sebastian

  Sebastian Martinez

  Sebastian Martinez replied 17 years, 11 months ago 1 Member · 0 Replies
• 0 Replies

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