This example creates a range of Interpolators and switches between them using a SwitchInterpolator.

 import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GraphicsConfigTemplate;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.io.File;
import java.net.URL;

import javax.media.j3d.Alpha;
import javax.media.j3d.AmbientLight;
import javax.media.j3d.Appearance;
import javax.media.j3d.AudioDevice;
import javax.media.j3d.Background;
import javax.media.j3d.BoundingSphere;
import javax.media.j3d.Bounds;
import javax.media.j3d.BranchGroup;
import javax.media.j3d.Canvas3D;
import javax.media.j3d.ColorInterpolator;
import javax.media.j3d.DirectionalLight;
import javax.media.j3d.GraphicsConfigTemplate3D;
import javax.media.j3d.Group;
import javax.media.j3d.Interpolator;
import javax.media.j3d.Locale;
import javax.media.j3d.Material;
import javax.media.j3d.PhysicalBody;
import javax.media.j3d.PhysicalEnvironment;
import javax.media.j3d.PositionInterpolator;
import javax.media.j3d.RotPosScalePathInterpolator;
import javax.media.j3d.RotationInterpolator;
import javax.media.j3d.ScaleInterpolator;
import javax.media.j3d.Switch;
import javax.media.j3d.SwitchValueInterpolator;
import javax.media.j3d.Transform3D;
import javax.media.j3d.TransformGroup;
import javax.media.j3d.TransparencyAttributes;
import javax.media.j3d.TransparencyInterpolator;
import javax.media.j3d.View;
import javax.media.j3d.ViewPlatform;
import javax.media.j3d.VirtualUniverse;
import javax.vecmath.Color3f;
import javax.vecmath.Point3d;
import javax.vecmath.Point3f;
import javax.vecmath.Quat4f;
import javax.vecmath.Vector3d;
import javax.vecmath.Vector3f;

import com.sun.j3d.audioengines.javasound.JavaSoundMixer;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.Primitive;
import com.sun.j3d.utils.geometry.Sphere;
import com.sun.j3d.utils.geometry.Text2D;

/**
 * This example creates a range of Interpolators and switches between them using
 * a SwitchInterpolator
 */
public class InterpolatorTest extends Java3dApplet {
  private static int m_kWidth = 400;

  private static int m_kHeight = 400;

  public InterpolatorTest() {
    initJava3d();
  }

  // scale eveything up so that moving from 0 to 1
  // is significant
  protected double getScale() {
    return 10.0;
  }

  // we want a black background
  protected Background createBackground() {
    return null;
  }

  protected BranchGroup createSceneBranchGroup() {
    BranchGroup objRoot = super.createSceneBranchGroup();

    // create a root TG in case we need to scale the scene
    TransformGroup objTrans = new TransformGroup();
    objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
    objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);

    // create the Appearance for the Shape3D
    Appearance app = new Appearance();

    // create a Material, modified by the ColorInterpolator
    Color3f objColor = new Color3f(1.0f, 0.7f, 0.8f);
    Color3f black = new Color3f(0.0f, 0.0f, 0.0f);
    Material mat = new Material(objColor, black, objColor, black, 80.0f);
    mat.setCapability(Material.ALLOW_COMPONENT_WRITE);
    app.setMaterial(mat);

    // create a TransparencyAttributes, modified by the
    // TransparencyInterpolator
    TransparencyAttributes transparency = new TransparencyAttributes();
    transparency.setCapability(TransparencyAttributes.ALLOW_VALUE_WRITE);
    transparency.setTransparencyMode(TransparencyAttributes.NICEST);
    app.setTransparencyAttributes(transparency);

    // create a Switch Node and set capabilities
    Switch switchNode = new Switch();
    switchNode.setCapability(Switch.ALLOW_SWITCH_WRITE);

    // create a Alpha object for the Interpolators
    Alpha alpha = new Alpha(-1, Alpha.INCREASING_ENABLE
        | Alpha.DECREASING_ENABLE, 500, 100, 5000, 2000, 1000, 5000,
        2000, 500);

    // add each BG and Interpolator as a child of the Switch Node
    TransformGroup tg = createSharedGroup(app);
    switchNode.addChild(createBranchGroup(tg, new ColorInterpolator(alpha,
        app.getMaterial())));

    tg = createSharedGroup(app);
    switchNode.addChild(createBranchGroup(tg, new PositionInterpolator(
        alpha, tg)));

    tg = createSharedGroup(app);
    switchNode.addChild(createBranchGroup(tg, new RotationInterpolator(
        alpha, tg)));

    tg = createSharedGroup(app);
    switchNode.addChild(createBranchGroup(tg, new ScaleInterpolator(alpha,
        tg)));

    tg = createSharedGroup(app);
    switchNode.addChild(createBranchGroup(tg, new TransparencyInterpolator(
        alpha, app.getTransparencyAttributes(), 0, 0.8f)));

    // define the data for the RotPosScalePathInterpolator
    float[] knots = { 0.0f, 0.1f, 0.2f, 0.3f, 0.4f, 0.6f, 0.8f, 0.9f, 1.0f };
    float[] scales = { 0.2f, 0.5f, 0.8f, 2.3f, 5.4f, 0.6f, 0.4f, 0.2f, 0.1f };
    Quat4f[] quats = new Quat4f[9];
    Point3f[] positions = new Point3f[9];

    quats[0] = new Quat4f(0.3f, 1.0f, 1.0f, 0.0f);
    quats[1] = new Quat4f(1.0f, 0.0f, 0.0f, 0.3f);
    quats[2] = new Quat4f(0.2f, 1.0f, 0.0f, 0.0f);
    quats[3] = new Quat4f(0.0f, 0.2f, 1.0f, 0.0f);
    quats[4] = new Quat4f(1.0f, 0.0f, 0.4f, 0.0f);
    quats[5] = new Quat4f(0.0f, 1.0f, 1.0f, 0.2f);
    quats[6] = new Quat4f(0.3f, 0.3f, 0.0f, 0.0f);
    quats[7] = new Quat4f(1.0f, 0.0f, 1.0f, 1.0f);
    quats[8] = quats[0];

    positions[0] = new Point3f(0.0f, 0.0f, -1.0f);
    positions[1] = new Point3f(1.0f, -2.0f, -2.0f);
    positions[2] = new Point3f(-2.0f, 2.0f, -3.0f);
    positions[3] = new Point3f(1.0f, 1.0f, -4.0f);
    positions[4] = new Point3f(-4.0f, -2.0f, -5.0f);
    positions[5] = new Point3f(2.0f, 0.3f, -6.0f);
    positions[6] = new Point3f(-4.0f, 0.5f, -7.0f);
    positions[7] = new Point3f(0.0f, -1.5f, -4.0f);
    positions[8] = positions[0];

    tg = createSharedGroup(app);

    // create the Interpolator
    RotPosScalePathInterpolator rotPosScalePathInterplator = new RotPosScalePathInterpolator(
        alpha, tg, new Transform3D(), knots, quats, positions, scales);

    // add a BG for the Interpolator
    switchNode.addChild(createBranchGroup(tg, rotPosScalePathInterplator));

    // create a RandomAlpha object to control a SwitchInterpolator
    // to set the Switches active child node randomly
    RandomAlpha randomAlpha = new RandomAlpha();

    // create the interpolator
    SwitchValueInterpolator switchInterpolator = new SwitchValueInterpolator(
        randomAlpha, switchNode);
    switchInterpolator.setSchedulingBounds(getApplicationBounds());

    // connect the scenegraph
    objTrans.addChild(switchNode);
    objTrans.addChild(switchInterpolator);

    // Set up the global lights
    Color3f lColor1 = new Color3f(0.7f, 0.7f, 0.7f);
    Vector3f lDir1 = new Vector3f(-1.0f, -1.0f, -1.0f);
    Color3f alColor = new Color3f(0.2f, 0.2f, 0.2f);

    AmbientLight aLgt = new AmbientLight(alColor);
    aLgt.setInfluencingBounds(getApplicationBounds());
    DirectionalLight lgt1 = new DirectionalLight(lColor1, lDir1);
    lgt1.setInfluencingBounds(getApplicationBounds());

    // add the lights
    objRoot.addChild(aLgt);
    objRoot.addChild(lgt1);

    // connect
    objRoot.addChild(objTrans);

    return objRoot;
  }

  // creates a BG containing:
  //  - a Link to the SharedGroup
  //  - The Interpolator
  //  - a Text2D label of the name of the Interpolator
  private BranchGroup createBranchGroup(TransformGroup bgShared,
      Interpolator interpolator) {
    BranchGroup bg = new BranchGroup();
    bg.addChild(bgShared);
    bg.addChild(interpolator);
    interpolator.setSchedulingBounds(getApplicationBounds());

    // strip the package name from szClass (everything before the final ".")
    String szClass = interpolator.getClass().getName();
    int nIndex = szClass.lastIndexOf(".");

    String szTrimedClass = szClass;

    if (nIndex > -1)
      szTrimedClass = szClass.substring(nIndex + 1, szClass.length());

    Text2D text = new Text2D(szTrimedClass, new Color3f(1, 1, 1),
        "SansSerif", 20, Font.PLAIN);
    bg.addChild(text);

    return bg;
  }

  // create a SharedGroup and populate with some child nodes
  private TransformGroup createSharedGroup(Appearance app) {
    TransformGroup tg = new TransformGroup();
    tg.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
    tg.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);

    tg.addChild(createGeometry(app, -0.5, -0.5, 0));
    tg.addChild(createGeometry(app, -0.5, 0.5, 0));
    tg.addChild(createGeometry(app, 0.5, 0.5, 0));
    tg.addChild(createGeometry(app, 0.5, -0.5, 0));

    return tg;
  }

  // create and position a Sphere using a parent TransformGroup
  TransformGroup createGeometry(Appearance app, double x, double y, double z) {
    Transform3D t3d = new Transform3D();
    t3d.setTranslation(new Vector3d(x, y, z));
    TransformGroup tg = new TransformGroup(t3d);

    tg.addChild(new Sphere(0.1f, Primitive.GENERATE_NORMALS, app));
    return tg;
  }

  public static void main(String[] args) {
    InterpolatorTest interpolatorTest = new InterpolatorTest();
    interpolatorTest.saveCommandLineArguments(args);

    new MainFrame(interpolatorTest, m_kWidth, m_kHeight);
  }
}

//this class defines an Alpha class that returns a random
//value every N milliseconds.

class RandomAlpha extends Alpha {
  protected long m_LastQueryTime = 0;

  protected float m_Alpha = 0;

  protected final int m_kUpdateInterval = 10000;

  public RandomAlpha() {
  }

  // core method override
  // returns the Alpha value for a given time
  public float value(long time) {
    if (System.currentTimeMillis() - m_LastQueryTime > m_kUpdateInterval) {
      m_LastQueryTime = System.currentTimeMillis();
      m_Alpha = (float) Math.random();
    }

    return m_Alpha;
  }
}

/*******************************************************************************
 * Copyright (C) 2001 Daniel Selman
 * 
 * First distributed with the book "Java 3D Programming" by Daniel Selman and
 * published by Manning Publications. http://manning.com/selman
 * 
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, version 2.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 * 
 * The license can be found on the WWW at: http://www.fsf.org/copyleft/gpl.html
 * 
 * Or by writing to: Free Software Foundation, Inc., 59 Temple Place - Suite
 * 330, Boston, MA 02111-1307, USA.
 * 
 * Authors can be contacted at: Daniel Selman: This email address is being protected from spambots. You need JavaScript enabled to view it.
 * 
 * If you make changes you think others would like, please contact one of the
 * authors or someone at the www.j3d.org web site.
 ******************************************************************************/

//*****************************************************************************
/**
 * Java3dApplet
 * 
 * Base class for defining a Java 3D applet. Contains some useful methods for
 * defining views and scenegraphs etc.
 * 
 * @author Daniel Selman
 * @version 1.0
 */
//*****************************************************************************

abstract class Java3dApplet extends Applet {
  public static int m_kWidth = 300;

  public static int m_kHeight = 300;

  protected String[] m_szCommandLineArray = null;

  protected VirtualUniverse m_Universe = null;

  protected BranchGroup m_SceneBranchGroup = null;

  protected Bounds m_ApplicationBounds = null;


  //  protected com.tornadolabs.j3dtree.Java3dTree m_Java3dTree = null;

  public Java3dApplet() {
  }

  public boolean isApplet() {
    try {
      System.getProperty("user.dir");
      System.out.println("Running as Application.");
      return false;
    } catch (Exception e) {
    }

    System.out.println("Running as Applet.");
    return true;
  }

  public URL getWorkingDirectory() throws java.net.MalformedURLException {
    URL url = null;

    try {
      File file = new File(System.getProperty("user.dir"));
      System.out.println("Running as Application:");
      System.out.println("   " + file.toURL());
      return file.toURL();
    } catch (Exception e) {
    }

    System.out.println("Running as Applet:");
    System.out.println("   " + getCodeBase());

    return getCodeBase();
  }

  public VirtualUniverse getVirtualUniverse() {
    return m_Universe;
  }

  //public com.tornadolabs.j3dtree.Java3dTree getJ3dTree() {
  //return m_Java3dTree;
  //  }

  public Locale getFirstLocale() {
    java.util.Enumeration e = m_Universe.getAllLocales();

    if (e.hasMoreElements() != false)
      return (Locale) e.nextElement();

    return null;
  }

  protected Bounds getApplicationBounds() {
    if (m_ApplicationBounds == null)
      m_ApplicationBounds = createApplicationBounds();

    return m_ApplicationBounds;
  }

  protected Bounds createApplicationBounds() {
    m_ApplicationBounds = new BoundingSphere(new Point3d(0.0, 0.0, 0.0),
        100.0);
    return m_ApplicationBounds;
  }

  protected Background createBackground() {
    Background back = new Background(new Color3f(0.9f, 0.9f, 0.9f));
    back.setApplicationBounds(createApplicationBounds());
    return back;
  }

  public void initJava3d() {
    //  m_Java3dTree = new com.tornadolabs.j3dtree.Java3dTree();
    m_Universe = createVirtualUniverse();

    Locale locale = createLocale(m_Universe);

    BranchGroup sceneBranchGroup = createSceneBranchGroup();

    ViewPlatform vp = createViewPlatform();
    BranchGroup viewBranchGroup = createViewBranchGroup(
        getViewTransformGroupArray(), vp);

    createView(vp);

    Background background = createBackground();

    if (background != null)
      sceneBranchGroup.addChild(background);

    //    m_Java3dTree.recursiveApplyCapability(sceneBranchGroup);
    //  m_Java3dTree.recursiveApplyCapability(viewBranchGroup);

    locale.addBranchGraph(sceneBranchGroup);
    addViewBranchGroup(locale, viewBranchGroup);

    onDoneInit();
  }

  protected void onDoneInit() {
    //  m_Java3dTree.updateNodes(m_Universe);
  }

  protected double getScale() {
    return 1.0;
  }

  public TransformGroup[] getViewTransformGroupArray() {
    TransformGroup[] tgArray = new TransformGroup[1];
    tgArray[0] = new TransformGroup();

    // move the camera BACK a little...
    // note that we have to invert the matrix as
    // we are moving the viewer
    Transform3D t3d = new Transform3D();
    t3d.setScale(getScale());
    t3d.setTranslation(new Vector3d(0.0, 0.0, -20.0));
    t3d.invert();
    tgArray[0].setTransform(t3d);

    return tgArray;
  }

  protected void addViewBranchGroup(Locale locale, BranchGroup bg) {
    locale.addBranchGraph(bg);
  }

  protected Locale createLocale(VirtualUniverse u) {
    return new Locale(u);
  }

  protected BranchGroup createSceneBranchGroup() {
    m_SceneBranchGroup = new BranchGroup();
    return m_SceneBranchGroup;
  }

  protected View createView(ViewPlatform vp) {
    View view = new View();

    PhysicalBody pb = createPhysicalBody();
    PhysicalEnvironment pe = createPhysicalEnvironment();

    AudioDevice audioDevice = createAudioDevice(pe);

    if (audioDevice != null) {
      pe.setAudioDevice(audioDevice);
      audioDevice.initialize();
    }

    view.setPhysicalEnvironment(pe);
    view.setPhysicalBody(pb);

    if (vp != null)
      view.attachViewPlatform(vp);

    view.setBackClipDistance(getBackClipDistance());
    view.setFrontClipDistance(getFrontClipDistance());

    Canvas3D c3d = createCanvas3D();
    view.addCanvas3D(c3d);
    addCanvas3D(c3d);

    return view;
  }

  protected PhysicalBody createPhysicalBody() {
    return new PhysicalBody();
  }

  protected AudioDevice createAudioDevice(PhysicalEnvironment pe) {
    JavaSoundMixer javaSoundMixer = new JavaSoundMixer(pe);

    if (javaSoundMixer == null)
      System.out.println("create of audiodevice failed");

    return javaSoundMixer;
  }

  protected PhysicalEnvironment createPhysicalEnvironment() {
    return new PhysicalEnvironment();
  }

  protected float getViewPlatformActivationRadius() {
    return 100;
  }

  protected ViewPlatform createViewPlatform() {
    ViewPlatform vp = new ViewPlatform();
    vp.setViewAttachPolicy(View.RELATIVE_TO_FIELD_OF_VIEW);
    vp.setActivationRadius(getViewPlatformActivationRadius());

    return vp;
  }

  protected Canvas3D createCanvas3D() {
    GraphicsConfigTemplate3D gc3D = new GraphicsConfigTemplate3D();
    gc3D.setSceneAntialiasing(GraphicsConfigTemplate.PREFERRED);
    GraphicsDevice gd[] = GraphicsEnvironment.getLocalGraphicsEnvironment()
        .getScreenDevices();

    Canvas3D c3d = new Canvas3D(gd[0].getBestConfiguration(gc3D));
    c3d.setSize(getCanvas3dWidth(c3d), getCanvas3dHeight(c3d));

    return c3d;
  }

  protected int getCanvas3dWidth(Canvas3D c3d) {
    return m_kWidth;
  }

  protected int getCanvas3dHeight(Canvas3D c3d) {
    return m_kHeight;
  }

  protected double getBackClipDistance() {
    return 100.0;
  }

  protected double getFrontClipDistance() {
    return 1.0;
  }

  protected BranchGroup createViewBranchGroup(TransformGroup[] tgArray,
      ViewPlatform vp) {
    BranchGroup vpBranchGroup = new BranchGroup();

    if (tgArray != null && tgArray.length > 0) {
      Group parentGroup = vpBranchGroup;
      TransformGroup curTg = null;

      for (int n = 0; n < tgArray.length; n++) {
        curTg = tgArray[n];
        parentGroup.addChild(curTg);
        parentGroup = curTg;
      }

      tgArray[tgArray.length - 1].addChild(vp);
    } else
      vpBranchGroup.addChild(vp);

    return vpBranchGroup;
  }

  protected void addCanvas3D(Canvas3D c3d) {
    setLayout(new BorderLayout());
    add(c3d, BorderLayout.CENTER);
    doLayout();
  }

  protected VirtualUniverse createVirtualUniverse() {
    return new VirtualUniverse();
  }

  protected void saveCommandLineArguments(String[] szArgs) {
    m_szCommandLineArray = szArgs;
  }

  protected String[] getCommandLineArguments() {
    return m_szCommandLineArray;
  }
}