Hi Sam! That spot is where the temperature sensor measures the temperature of the current layer. We cannot position parts there because it would distort the measurements. So indeed, we need to keep that area clear 👍

@@PartsondemandEu Thank you for the quick and practical response! It sounds a bit like white balance of a photo that I can define by finding one area that is supposed to be white. At 2:33 you mention that the configuration of the heating elements cause a nice and even heat distribution. So that heat distribution is based on the temperature measurement in the red area, is that correct? Do the (three or four) heating elements control the temperature independently or is their configuration working as one heating? More regards, Sam

@@VideoSamukun the heaters are calibrated in relation to eachother but act as a single heating element. So they're all controlled by that single temperature sensor.

@@PartsondemandEu Thanks again for your response! I'm glad I found your video.