Dear Customer, thank you for using our iLCD step files. For viewing our step models, you may use the STP Viewer (free download from http://stpviewer.com/). The software used to create the step files does not allow us to export CAD models with rounded surfaces. This may cause troubles when combining our iLCD panel model with your construction. In order to get a logical connection to the mounting (e.g., screws or bolts), just define the center and punch through again. Hint: the diameter of the drill holes corresponds to the maximum distance of 2 points of a polygon. If you have any further questions, please do not hesitate to ask us. demmel products gmbh support@demmel.com