A common request when processing models is to create a plan that matches the occlusal plane of the arches. To keep it simple the algorithms of the Medit iScan will create a plane from the lowest data point on one side of the model to the highest point on the model on the contralateral side. You can control this plane by using the edit tool in the arches and crop out data so that you help the software to find this plane more easily. The more discrepancy there is between these data points will render drastically different planes than the occlusal scheme as seen in the attached photo. Besides, the less data you have to process, the faster the models will be rendered.