public CameraApp() { ball.setXYZ(0.0, 0.0, 0.0); ball.setSizeXYZ(0.5, 0.5, 0.5); ball.getStyle().setFillColor(Color.YELLOW); // right wall wallR.setXYZ(6.0, 0.0, 0.0); wallR.setSizeXYZ(0.2, 4.0, 4.0); wallR.getStyle().setFillColor(Color.GREEN); // left wall wallL.setXYZ(-6.0, 0.0, 0.0); wallL.setSizeXYZ(0.2, 4.0, 4.0); wallL.getStyle().setFillColor(Color.GREEN); // Add the objects panel.setPreferredMinMax(-6, 6, -6, 6, -6, 6); panel.getInteractionTarget(org.opensourcephysics.display3d.core.DrawingPanel3D.TARGET_PANEL); panel.addInteractionListener(this); panel.addElement(ball); panel.addElement(wallR); panel.addElement(wallL); DrawingFrame3D frame = new DrawingFrame3D(); frame.setDrawingPanel3D(panel); }