public void ModifyTriangulate() { Triangulations triangulation = new Triangulations(); AC_Transactions tr = new AC_Transactions(); PromptEntityOptions options = new PromptEntityOptions("Pick a Line to modify Triangulations"); options.SetRejectMessage("not valid Object \n"); options.AddAllowedClass(typeof(Line), true); PromptEntityResult sel = tr.AC_Doc.Editor.GetEntity(options); if (sel.Status == PromptStatus.OK) { triangulation.Modify((AC_Line)tr.openObjectErased(sel.ObjectId)); } }