## On this page # Example 16 - C# Last update: 17.07.2025 # C# using System; using [ZOSAPI](namespace_z_o_s_a_p_i.xhtml); namespace CSharpUserOperandApplication { class Program { static void Main(string[] args) { // Find the installed version of OpticStudio bool isInitialized = ZOSAPI_NetHelper.ZOSAPI_Initializer.Initialize(); // Note -- uncomment the following line to use a custom initialization path //bool isInitialized = ZOSAPI\_NetHelper.ZOSAPI\_Initializer.Initialize(@"C:\\Program Files\\OpticStudio\\"); if (isInitialized) { LogInfo("Found OpticStudio at: " + ZOSAPI_NetHelper.ZOSAPI_Initializer.GetZemaxDirectory()); } else { HandleError("Failed to locate OpticStudio!"); return; } BeginUserOperand(); } static void BeginUserOperand() { // Create the initial connection class [ZOSAPI\_Connection](class_z_o_s_a_p_i_1_1_z_o_s_a_p_i___connection.xhtml) TheConnection = new [ZOSAPI\_Connection](class_z_o_s_a_p_i_1_1_z_o_s_a_p_i___connection.xhtml)(); // Attempt to connect to the existing OpticStudio instance [IZOSAPI\_Application](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml) TheApplication = null; try { TheApplication = TheConnection.[ConnectToApplication](class_z_o_s_a_p_i_1_1_z_o_s_a_p_i___connection.xhtml#aeb9010dade0f9685d455425d7eb7d8f5)(); // this will throw an exception if not launched from OpticStudio } catch (Exception ex) { HandleError(ex.Message); return; } if (TheApplication == null) { HandleError("An unknown connection error occurred!"); return; } // Check the connection status if (!TheApplication.[IsValidLicenseForAPI](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a5b8d6c216c668d13d6dcb870698c247f)) { HandleError("Failed to connect to OpticStudio: " + TheApplication.[LicenseStatus](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a95179eb8038b629caa12397723aacb3a)); return; } if (TheApplication.[Mode](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a8d2a89bafe9778c14f592276e5a5eb19) != [ZOSAPI\_Mode](namespace_z_o_s_a_p_i.xhtml#a254f5f6cb4ff37c2245b456b9bb79d2a).Operand) { HandleError("User plugin was started in the wrong mode: expected Operand, found " + TheApplication.[Mode](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a8d2a89bafe9778c14f592276e5a5eb19).ToString()); return; } // Read the operand arguments double Hx = TheApplication.[OperandArgument1](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#ae50eae8bffec8ed4b4cf511b52b8ccf4); double Hy = TheApplication.[OperandArgument2](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a7fc25b6936d0b0b840af213bb54d7314); double Px = TheApplication.[OperandArgument3](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#adefae0ab7222380382b8457207120086); double Py = TheApplication.[OperandArgument4](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#ac14d8524751a4b765e91df2535542d48); // Initialize the output array int maxResultLength = TheApplication.[OperandResults](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a46fc7da26be5a482b4991b3b7157f59e).Length; double[] operandResults = new double[maxResultLength]; [IOpticalSystem](interface_z_o_s_a_p_i_1_1_i_optical_system.xhtml) TheSystem = TheApplication.[PrimarySystem](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#aca8045fe84351622e0ee58814a2a3364); // Add your custom code here... // This is an example that calculates the sum of absolute distance between surfaces. // Hx -> Surf1 // Hy -> Surf2 // Read the operand arguments (Note that we aren't using operand 3 and 4) int surf1 = (int)TheApplication.[OperandArgument1](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#ae50eae8bffec8ed4b4cf511b52b8ccf4); int surf2 = (int)TheApplication.[OperandArgument2](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a7fc25b6936d0b0b840af213bb54d7314); //double x = TheApplication.OperandArgument3; //double y = TheApplication.OperandArgument4; //Make the sum of the absolute value of each surface thickness [ZOSAPI.Editors.LDE.ILDERow](interface_z_o_s_a_p_i_1_1_editors_1_1_l_d_e_1_1_i_l_d_e_row.xhtml) surf; double thic = 0; if (surf1 <= surf2) { for (int i = surf1; i <= surf2; i++) { surf = TheSystem.[LDE](interface_z_o_s_a_p_i_1_1_i_optical_system.xhtml#a942995136e3c3cf875cc1fde38d33477).GetSurfaceAt(i); thic = thic + Math.Abs(surf.[Thickness](interface_z_o_s_a_p_i_1_1_editors_1_1_l_d_e_1_1_i_l_d_e_row.xhtml#a06e8f1479eeba5ae70b2f6082bb5ee71)); } operandResults[0] = thic; } else { operandResults[0] = 1e9; // invalid input } // Clean up FinishUserOperand(TheApplication, operandResults); } static void FinishUserOperand([IZOSAPI\_Application](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml) TheApplication, double[] resultData) { // Note - OpticStudio will wait for the operand to complete until this application exits if (TheApplication != null) { TheApplication.[OperandResults](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a46fc7da26be5a482b4991b3b7157f59e).WriteData(resultData.Length, resultData); } } static void LogInfo(string message) { // TODO - add custom logging Console.WriteLine(message); } static void HandleError(string errorMessage) { // TODO - add custom error handling throw new Exception(errorMessage); } } } [ZOSAPI.ZOSAPI\_Connection](class_z_o_s_a_p_i_1_1_z_o_s_a_p_i___connection.xhtml) **Definition:** ZemaxService.cs:198 [ZOSAPI.ZOSAPI\_Connection.ConnectToApplication](class_z_o_s_a_p_i_1_1_z_o_s_a_p_i___connection.xhtml#aeb9010dade0f9685d455425d7eb7d8f5) IZOSAPI_Application ConnectToApplication() Attempts to connect to Optic Studio. This will only succeed when the client application was launched ... **Definition:** ZemaxService.cs:536 [ZOSAPI.Editors.LDE.ILDERow](interface_z_o_s_a_p_i_1_1_editors_1_1_l_d_e_1_1_i_l_d_e_row.xhtml) All data for a Lens Data Editor surface. This interface can be accessed via the ILensDataEditor inter... **Definition:** InterfacesLDE.cs:791 [ZOSAPI.Editors.LDE.ILDERow.Thickness](interface_z_o_s_a_p_i_1_1_editors_1_1_l_d_e_1_1_i_l_d_e_row.xhtml#a06e8f1479eeba5ae70b2f6082bb5ee71) double Thickness Gets or sets the surface thickness. **Definition:** InterfacesLDE.cs:1009 [ZOSAPI.IOpticalSystem](interface_z_o_s_a_p_i_1_1_i_optical_system.xhtml) Represent a complete optical system. A IOpticalSystem corresponds to a single .ZMX file.... **Definition:** Interfaces.cs:687 [ZOSAPI.IOpticalSystem.LDE](interface_z_o_s_a_p_i_1_1_i_optical_system.xhtml#a942995136e3c3cf875cc1fde38d33477) ILensDataEditor LDE Gets the lens data editor. **Definition:** Interfaces.cs:865 [ZOSAPI.IZOSAPI\_Application](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml) This interface contains all information about the current ZOS-API connection, as well as methods for ... **Definition:** Interfaces.cs:261 [ZOSAPI.IZOSAPI\_Application.OperandResults](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a46fc7da26be5a482b4991b3b7157f59e) IVectorData OperandResults In Operand mode, used to set the output data. **Definition:** Interfaces.cs:543 [ZOSAPI.IZOSAPI\_Application.IsValidLicenseForAPI](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a5b8d6c216c668d13d6dcb870698c247f) bool IsValidLicenseForAPI Gets a value indicating whether this the API is currently useable. **Definition:** Interfaces.cs:287 [ZOSAPI.IZOSAPI\_Application.OperandArgument2](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a7fc25b6936d0b0b840af213bb54d7314) double OperandArgument2 Argument 2 - Hy. **Definition:** Interfaces.cs:567 [ZOSAPI.IZOSAPI\_Application.Mode](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a8d2a89bafe9778c14f592276e5a5eb19) ZOSAPI_Mode Mode Gets the current connetion mode. Use this to check if Optic Studio is expecting a user operand / anal... **Definition:** Interfaces.cs:306 [ZOSAPI.IZOSAPI\_Application.LicenseStatus](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#a95179eb8038b629caa12397723aacb3a) LicenseStatusType LicenseStatus Gets the license status. Note that this displays the license edition if successful,... **Definition:** Interfaces.cs:280 [ZOSAPI.IZOSAPI\_Application.OperandArgument4](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#ac14d8524751a4b765e91df2535542d48) double OperandArgument4 Argument 4 - Py. **Definition:** Interfaces.cs:575 [ZOSAPI.IZOSAPI\_Application.PrimarySystem](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#aca8045fe84351622e0ee58814a2a3364) IOpticalSystem PrimarySystem Gets the primary system. When Mode is ZOSAPI_Mode.Server, this will initially be an empty sequential ... **Definition:** Interfaces.cs:328 [ZOSAPI.IZOSAPI\_Application.OperandArgument3](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#adefae0ab7222380382b8457207120086) double OperandArgument3 Argument 3 - Px. **Definition:** Interfaces.cs:571 [ZOSAPI.IZOSAPI\_Application.OperandArgument1](interface_z_o_s_a_p_i_1_1_i_z_o_s_a_p_i___application.xhtml#ae50eae8bffec8ed4b4cf511b52b8ccf4) double OperandArgument1 Argument 1 - Hx. **Definition:** Interfaces.cs:555 [ZOSAPI](namespace_z_o_s_a_p_i.xhtml) The ZOSAPI namespace contains classes for initially connecting to zemax. See also ZOSAPI_Connection,... **Definition:** IAS_FieldCurvatureAndDistortion.cs:5 [ZOSAPI.ZOSAPI\_Mode](namespace_z_o_s_a_p_i.xhtml#a254f5f6cb4ff37c2245b456b9bb79d2a) ZOSAPI_Mode **Definition:** Interfaces.cs:77