public Canvas3D getCanvas3D(int canvasNum) { if (canvasNum > canvases.length) { return null; } return canvases[canvasNum];
public Canvas3D getCanvas3D() { return canvases[0];
    public Canvas3D getCanvas3D(int canvasNum) {	if (canvasNum > canvases.length) {	    return null;	}        return canvases[canvasNum];    }