RevitAddin Command to edit a selected DirectShape, if DirectShape has a DirectShapeType the type is edited instead.

CommandShapeEdit.cs

using Autodesk.Revit.Attributes;
using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using Autodesk.Revit.UI.Selection;
using System.Linq;

namespace RevitAddin.Commands
{
    [Transaction(TransactionMode.Manual)]
    public class CommandShapeEdit : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elementSet)
        {
            UIApplication uiapp = commandData.Application;

            UIDocument uidoc = uiapp.ActiveUIDocument;
            Document document = uidoc.Document;
            View view = uidoc.ActiveView;
            Selection selection = uidoc.Selection;

            var elements = selection.GetElementIds().Select(id => document.GetElement(id));

            var shapes = elements.OfType<DirectShape>();

            using (Transaction transaction = new Transaction(document))
            {
                transaction.Start("Shape Edit");

                var lines = new[] {
                    Line.CreateBound(-XYZ.BasisX, XYZ.BasisX),
                    Line.CreateBound(-XYZ.BasisY, XYZ.BasisY),
                    Line.CreateBound(-XYZ.BasisZ, XYZ.BasisZ)
                };

                foreach (var shape in shapes)
                {
                    if (document.GetElement(shape.TypeId) is DirectShapeType shapeType)
                    {
                        shapeType.SetShape(lines);
                        continue;
                    }
                    shape.SetShape(lines);
                }
                transaction.Commit();
            }

            return Result.Succeeded;
        }
    }

}