Acrobat 3D Controlling Animations

Question

Acrobat 3D Controlling Animations

Answer 1

You have to use Acrobat 3D JavaScript to control the playback. There are two options, neither of which is particularly simple:
1) Recreate the U3D model so it contains several different animation "sequences" rather than one long one. In JS you can then select which of them you want to be active (by name or number) using the scene.activateAnimation() method, so only that sequence plays back when the toolbar buttons are used. Starting and pausing playback is done using runtime.pause() and runtime.play(). You'd do something like this:
var _anim = scene.animations.getByIndex(3); // pick the fourth one
scene.activateAnimation(_anim);
runtime.play();
2) Write your own timeEventHandler(). This is also the only way to change the speed of playback or make it run in reverse. Note that unlike a video file, 3D animations do not have a uniform series of "frames" you can step through; they have keyframes defined by time intervals in seconds and between that all the movements are interpolated. Here's a typical use for TimeEventHandler, slow-motion playback:
var animSpeedFactor = 0.5;
function playAnimSlowly() {
    if(_anim.currentTime >= _anim.endTime)  _anim.currentTime = _anim.startTime;
    if (typeof _animTimer != "undefined") runtime.removeEventHandler(_animTimer);
    var _tps = _anim.currentTime;
    _animTimer = new TimeEventHandler();
    _animTimer.onTimeChange = true;
    _animTimer.onEvent = function(event) {
      _tps += event.deltaTime/animSpeedFactor;
      if (_tps <= _anim.endTime) _anim.currentTime = _tps;
      else {
      _anim.currentTime = _anim.endTime;
      runtime.removeEventHandler(_animTimer);
    runtime.addEventHandler(_animTimer);
function resetAnimSpeed(_asf) {
    animSpeedFactor = _asf;
    if (typeof _animTimer != "undefined") runtime.removeEventHandler(_animTimer);
The functions are documented in the Acrobat SDK under the "JavaScript > JavaScript for 3D Annotations" chapter.