private float guessDiameter(){
		//Read user defined environment variable if exists
		try {
			String dia = System.getenv("FILAMENT_DIAMETER");
			if(dia != null){
				//System.out.println("Use env value FILAMENT_DIAMETER="+dia);
				return Float.parseFloat(dia);
			}
		} catch (NumberFormatException e1) {
		}
		
		//get diameter from comments in gcode file
		try {
			GCodeStore codes = getGcodes();
			for (GCode gCode : codes) {
				//Ignore comments behind gcodes
				if (gCode.isComment()){
					//System.out.println("COMMENT"+gCode.getComment());
					if(gCode.getComment().matches(".*FILAMENT_DIAMETER\\s=.*")){ //SLICER
						//System.out.println("MATCHES:"+gCode.getComment());
						String[] res =gCode.getComment().split("=");
						return Float.parseFloat(res[1]);
					}else if(gCode.getComment().matches(".*FILAMENT_DIAMETER_.*")){ //SKEINFORGE
						//System.out.println("MATCHES:"+gCode.getComment());
						String[] res =gCode.getComment().split("[:<]");
						return Float.parseFloat(res[2]);					
					}
				}
			}
		} catch (Exception e) {
			//Comment parsing failed
		}
	//	System.err.println("Failed to parse GCODE comments for filament diameter. Fallback to guessing.");
		//Fallback ... no comments found
		isguessed=true;
		//Tried many formulars but there is no good way to guess the diameter (too many unknowns)
		//
		float exRadius=getAvgLayerHeight()/2; 
		float WOT = 2.1f;  //Assume a wide over thickness value of ~2.1 (heavily depends on nozzel size)
		double extrArea =  exRadius*(exRadius*WOT) * Math.PI; //Fläche extruded mm2
		double menge = extrArea*getDistance();
		double sizeArea = menge/getExtrusion();
		double guessedDia = Math.sqrt(sizeArea/Math.PI)*2;
	//	System.out.println("Extr menge mm3:"+menge/1000+" Estimate dia:"+guessedDia);
		
		//Either take 1.75 or 3mm
		if(guessedDia > 2.45f){
			return 3;
		}else if(guessedDia < 2.05f){
			return 1.75f;
		}
		//use 3
		System.out.println("Unable to detect diameter - Fallback to 3mm.\nPlease set environment variable FILAMENT_DIAMETER");
		return 3;
	}