Renderer queueing geometry updates until OOM

Question

Hi,
we have some quite annoying problem in a project using j3d. We issue quite some geometry changes to show processdata. It seems like these changes/updates are queued when the frame containing the canvas becomes inactive, like minimizing it or changing workspaces. We already changed the code to use async (GeometryUpdater) updates and by_ref coordinates, but that didn't help , as soon as the frame is hidden the heap memory usage increases really fast (when geometry changes happen), gc() doesn't help because all the memory is still referenced.
The heap is mainly filled up with Object[] and J3DMessage objects, which was the expected result when queueing up messages which aren't rendered.
I am just really wondering why that happens? I already digged through the j3d source but didn't have a clue, also searching the web didn't give any useful information on this point as it seems that we are the only project which uses geometrychanges that heavily.
I hope that someone can point me to the right direction (it's probably something small and stupid). I can also post some example code if my problem isn't clear.
Best regards
Georg

Answer 1

Hi,
have you ever got familiar with Java 3D's Behavior node? The use of a Timer isn't advisable for the desired 'task'.
"Behavior nodes provide the means for animating objects, processing keyboard and mouse inputs, reacting to movement, and enabling and processing pick events. Behavior nodes contain Java code and state variables. A Behavior node's Java code can interact with Java objects, change node values within a Java 3D scene graph, change the behavior's internal state-in general, perform any computation it wishes."
Please, run this code and inform us how it behaves.
August
import java.awt.Color;
import java.awt.GraphicsConfiguration;
import java.util.Enumeration;
import java.util.Timer;
import java.util.TimerTask;
import javax.media.j3d.*;
import javax.swing.*;
import javax.vecmath.*;
import com.sun.j3d.utils.universe.SimpleUniverse;
public class GeometryUpdateIssue extends JFrame {
    private QuadArray qa = new QuadArray(16,
                    GeometryArray.COORDINATES|GeometryArray.COLOR_3);
    private double points[] = new double[48];
    public GeometryUpdateIssue() {
        setSize(500, 500);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0), 10.0);
        GraphicsConfiguration graphConfig = SimpleUniverse.getPreferredConfiguration();
        Canvas3D canvas3D = new Canvas3D(graphConfig);
        SimpleUniverse simpleUni = new SimpleUniverse(canvas3D);
        BranchGroup sceneGraph = new BranchGroup();
        sceneGraph.setBoundsAutoCompute(true);
        qa.setCapability(GeometryArray.ALLOW_COORDINATE_WRITE);
        Background background = new Background(new Color3f(Color.WHITE));
        background.setApplicationBounds(bounds);
        sceneGraph.addChild(background);
        for (int i : new int[]{5, 8, 14, 15, 17, 18, 20, 23, 24, 26, 27, 30, 33, 35, 36, 45}) {
                points[i] = 0.2;
        setHeight(0.5);
        Shape3D s = new Shape3D(qa);
        TransformGroup objTrans = new TransformGroup();
        objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
        Transform3D t3d = new Transform3D();
        t3d.setTranslation(new Vector3f(0.0f, -0.4f, 0.0f));
        objTrans.setTransform(t3d);
        TransformGroup objTrans2 = new TransformGroup();
        objTrans2.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
        Transform3D yAxis = new Transform3D();
        Alpha rotationAlpha = new Alpha(-1, 4000);
        RotationInterpolator rotator = new RotationInterpolator(
                        rotationAlpha, objTrans2, yAxis,
                        0.0f, (float) Math.PI*2.0f);
        rotator.setSchedulingBounds(bounds);
        sceneGraph.addChild(rotator);
        objTrans.addChild(objTrans2);
        objTrans2.addChild(s);
        sceneGraph.addChild(objTrans);
        GeomUpdater geomUpdater = new GeomUpdater(5);
        geomUpdater.setSchedulingBounds(bounds);
        sceneGraph.addChild(geomUpdater);
        simpleUni.addBranchGraph(sceneGraph);
        simpleUni.getViewingPlatform().setNominalViewingTransform();
        add(canvas3D);
        new Timer().scheduleAtFixedRate(new TimerTask() {
            int i = 0;
            @Override
            public void run() {
                setHeight((++i)%10/10.0);
                setHeight((++i)%10/10.0);
                setHeight((++i)%10/10.0);
                setHeight((++i)%10/10.0);
        }, 1000, 5);
    private void setHeight(double h) {
        for (int i : new int[]{7, 10, 19, 22, 31, 34, 43, 46}) {
                points[i] = h;
        qa.setCoordinates(0, points);
    private class GeomUpdater extends Behavior {
        private int i = 0;
        private WakeupOnElapsedTime elapsedTime = null;
        GeomUpdater(long milliseconds) {
            elapsedTime = new WakeupOnElapsedTime(milliseconds);
        @Override
        public void initialize() {
            this.wakeupOn(elapsedTime);
        @Override
        public void processStimulus(Enumeration criteria) {
            setHeight((++i)%10/10.0);
            setHeight((++i)%10/10.0);
            setHeight((++i)%10/10.0);
            setHeight((++i)%10/10.0);
            this.wakeupOn(elapsedTime);
    public static void main(String[] args) {
        new GeometryUpdateIssue().setVisible(true);
}