private static DB.Level GetLevelClosestToZ(double z, DB.Document document, out double offsetFromLevel)
{
var levels = new DB.FilteredElementCollector(document).OfClass(typeof(DB.Level))
.Cast <DB.Level>()
.OrderBy(x => Math.Abs(z - x.ProjectElevation));
var level = levels.FirstOrDefault();
offsetFromLevel = z - level.ProjectElevation;
return(level);
}
