Solved How do I adjust the beds centering in gcode?

You are aware that the printer prints where it can and that the graphics printed on the bed have no relation to the actual printable area. You can visually center as you have done, but all that really does is make you feel better and limits the area you can print from.

 

On larger prints you lose heating area anyway you move the piece. The heater only covers about 2/3 of the entire build area. Please note that in order for the printer to determine where it prints, it only determines positions X0, Y0 and Z0. The entire movement of the X, Y and Z axes are not as advertised, but are about 5 - 8% smaller. The 0 positions are fixed by the linear motion hardware, regardless where the heater pad is installed.

This would all have been a moot point if the heater pad was bigger and covered the entire build area but it isn't. The best way top determine where you can actually print, you can home X and Y then move both to about 220 mm, from there move each axis 1 mm at a time until you hit the physical limit. I think on unmodified R1/R1+ should be about X230, Y240. Now once you determine the real world limits and divide each axis by 2 you have the physical center of the build area. Whether or not that is the physical middle of the heated area, is simply a matter of luck of the draw. Some heaters will be centered better than others. If yours is centered then you should play the lottery.

Simply put if you want MatterControl to center the objects in the true center of the build area rather than the visual center, then you need to determine the physical limits and input those in both numbers in both the firmware as well as the MatterControl printer profile. It is the only accurate way to do it.