A mesh repair application within a rendering engine is configured to generate a graphical user interface that allows an end-user of the rendering engine to inspect and repair various defects associated with a three-dimensional model. The outer housing and inner race are respectively rotatable about a first and second rotation axes, and moveable relative to one another to change an angle between the rotation axes. An image included in reception data obtained via communication is outputted to a television. The apparatus comprises also a second driving roller means adapted to engage the portion of the web of paper being left on the paper-supporting plate after the sheet has been cut off and to pull said portion temporarily backwards in such a manner towards the paper supply while the sheet is being inverted that said sheet can be guided into the printer without colliding with the web of paper. Performance characteristic data corresponding to a current build of the software under development are compared to the performance change gradients.