private void addProperty(NVApi.ModelItem PropModelItem, string strPropName, string strPropValue) { try { COM.InwOpState10 state; state = ComApiBridge.State; // get current selection NVApi.ModelItemCollection modelItemCollectionIn = new NVApi.ModelItemCollection(); modelItemCollectionIn.Add(PropModelItem); // get the selection in COM Autodesk.Navisworks.Api.Interop.ComApi.InwOpSelection comSelectionOut = ComApiBridge.ToInwOpSelection(modelItemCollectionIn); // get paths within the selection COM.InwSelectionPathsColl oPaths = comSelectionOut.Paths(); COM.InwOaPath3 oPath = (COM.InwOaPath3)oPaths.Last(); // get properties collection of the path COM.InwGUIPropertyNode2 propn = (COM.InwGUIPropertyNode2)state.GetGUIPropertyNode(oPath, true); // create new property category // (new tab in the properties dialog) COM.InwOaPropertyVec newPvec = (COM.InwOaPropertyVec)state.ObjectFactory(COM.nwEObjectType.eObjectType_nwOaPropertyVec, null, null); // create new property COM.InwOaProperty newP = (COM.InwOaProperty)state.ObjectFactory(COM.nwEObjectType.eObjectType_nwOaProperty, null, null); // set the name, username and value of the new property newP.name = "lc" + strPropName; newP.UserName = strPropName; newP.value = strPropValue; // add the new property to the new property category newPvec.Properties().Add(newP); // add the new property category to the path propn.SetUserDefined(0, "NV-AddedProety", "lcNVAddedProety", newPvec); } catch { throw; } }