Re: roof covering Hello; First of all, if it is the purlin that you will define the coating, on which floor you have defined the purlins, define the coating on that floor on the screen. Make sure that you do not remove the overlays from the image by going to the filter section from the icons in the upper right of the perspective screen. For other cases, images will be self explanatory. If you cannot define a coating after these steps, please send your project to technical support with a short explanation. Good work.