I created a 3D site model from 3D poly contour lines in Vectorworks. I would like to use the site model to iterate and test designs on the site, and I am trying to create a building pad. After I create a building pad and update the site model, I can see the new topography; however, I can't seem to be able to select the building pad to edit it, change it, and iterate. Any help would be appreciated. Thanks!