How to set axis (triad) at fixed position on screen in JavaFX?

Question

How to set axis (triad) at fixed position on screen in JavaFX? I am currently developing one application in which I want to show axis (triad) at fixed position on my screen

Answer 1

How to set axis (triad) at fixed position…I also wanted axis rotation in sync with box.

In this example, the Content.create() factory method translates the triad of axes is to the point

P = (-size / 2, size / 2, 0)

Because its separate group has no transforms, the triad's origin "sticks" to that point in the space viewed by the camera.

In contrast, the example below translates the triad of axes is to the point

P = (-size / 2, size / 2, size / 2)

Because the axes are in the same group as box, they undergo the same rotations.

import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.PerspectiveCamera;
import javafx.scene.Scene;
import javafx.scene.input.MouseEvent;
import javafx.scene.input.ScrollEvent;
import javafx.scene.paint.Color;
import javafx.scene.paint.PhongMaterial;
import javafx.scene.shape.Box;
import javafx.scene.transform.Rotate;
import javafx.stage.Stage;

/**
 * @see https://stackoverflow.com/a/37714700/230513
 * @see https://stackoverflow.com/a/37685167/230513
 * @see https://stackoverflow.com/a/37370840/230513
 */
public class TriadBox extends Application {

    private static final double SIZE = 300;
    private final Content content = Content.create(SIZE);

    private static final class Content {

        private static final double WIDTH = 3;
        private final Group group = new Group();
        private final Rotate rx = new Rotate(0, Rotate.X_AXIS);
        private final Rotate ry = new Rotate(0, Rotate.Y_AXIS);
        private final Rotate rz = new Rotate(0, Rotate.Z_AXIS);
        private final Box xAxis;
        private final Box yAxis;
        private final Box zAxis;
        private final Box box;

        private static Content create(double size) {
            Content c = new Content(size);
            c.group.getChildren().addAll(c.box, c.xAxis, c.yAxis, c.zAxis);
            c.group.getTransforms().addAll(c.rz, c.ry, c.rx);
            return c;
        }

        private Content(double size) {
            xAxis = createBox(size * 2, WIDTH, WIDTH);
            xAxis.setTranslateY(size / 2);
            xAxis.setTranslateZ(size / 2);
            yAxis = createBox(WIDTH, size * 2, WIDTH);
            yAxis.setTranslateX(-size / 2);
            yAxis.setTranslateZ(size / 2);
            zAxis = createBox(WIDTH, WIDTH, size * 2);
            zAxis.setTranslateX(-size / 2);
            zAxis.setTranslateY(size / 2);
            double edge = 3 * size / 4;
            box = new Box(edge, edge, edge);
            box.setMaterial(new PhongMaterial(Color.CORAL));
        }

        private Box createBox(double w, double h, double d) {
            Box b = new Box(w, h, d);
            b.setMaterial(new PhongMaterial(Color.AQUA));
            return b;
        }
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("JavaFX 3D");
        Scene scene = new Scene(content.group, SIZE * 2, SIZE * 2, true);
        primaryStage.setScene(scene);
        scene.setFill(Color.BLACK);
        scene.setOnMouseMoved((final MouseEvent e) -> {
            if (e.isShiftDown()) {
                content.rz.setAngle(e.getSceneX() * 360 / scene.getWidth());
            } else {
                content.rx.setAngle(e.getSceneY() * 360 / scene.getHeight());
                content.ry.setAngle(e.getSceneX() * 360 / scene.getWidth());
            }
        });
        PerspectiveCamera camera = new PerspectiveCamera(true);
        camera.setFarClip(SIZE * 6);
        camera.setTranslateZ(-3.5 * SIZE);
        scene.setCamera(camera);
        scene.setOnScroll((final ScrollEvent e) -> {
            camera.setTranslateZ(camera.getTranslateZ() + e.getDeltaY());
        });
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}