# Frequently Asked Questions (FAQ)

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• ### I get Warning No. 465: "Line [No.] is simultaneously used as a boundary line of a surface and an opening." Do I have to adjust anything?

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Openings are used to create cutouts into surfaces. In areas where openings are placed, no finite elements are generated nor are surface loads applied. Openings on the edge of a surface are allowed as well.

The boundary lines of a surface must form a closed continuous line. In our example, the warning message only appears for Surface 1, but not for Surface 2. Surface 1 is defined by three boundary lines on one edge, but Surface 2 not.

A comparison of the results shows that you can model your surfaces with openings in all three cases.

• ### How can I enter or read out a response spectrum via the COM interface in DYNAM Pro?

The COM interface allows you to read out or create a user-defined response spectrum in RFEM and RSTAB.

For the conversion, it is necessary to get the interface to the module (IDynamModule) via the interface to the RFEM model (IModel). This interface is then used to create the module case (IModuleCase). IModuleCase includes the GetRSParams function, which can be used to read out the parameters for the response spectrum. On the other hand, the SetRSParams function can write new data. The following example code clarifies it:

Dim iApp As RFEM5.ApplicationDim iMod As RFEM5.modelSet iApp = GetObject(, "RFEM5.Application")Dim rs_no As Integerrs_no = 1On Error GoTo e    ' Checks RS-COM license and locks the application for using by COM.    iApp.LockLicense    Set iMod = iApp.GetActiveModel    '  get module interface    Dim iDyn As IDynamModule    Set iDyn = iMod.GetModule("DynamPro")    '  get module case interface    Dim iDynCase As IModuleCase    Set iDynCase = iDyn.GetData        '  set response spectra parameters    Dim rspara As RSParams    rspara = iDynCase.GetRSParams(rs_no)        Dim rs_spec(0 To 10) As RSTableRow        Dim index As Integer    index = 0    rs_spec(index).s = 0.6    rs_spec(index).T = 0        index = 1    rs_spec(index).s = 1.33    rs_spec(index).T = 0.153        index = 2    rs_spec(index).s = 1.33    rs_spec(index).T = 0.4        index = 3    rs_spec(index).s = 1.204    rs_spec(index).T = 0.443        index = 4    rs_spec(index).s = 1.07    rs_spec(index).T = 0.5        index = 5    rs_spec(index).s = 0.7    rs_spec(index).T = 0.761        index = 6    rs_spec(index).s = 0.508    rs_spec(index).T = 1.051        index = 7    rs_spec(index).s = 0.367    rs_spec(index).T = 1.453        index = 8    rs_spec(index).s = 0.267    rs_spec(index).T = 1.995        index = 9    rs_spec(index).s = 0.16    rs_spec(index).T = 2.584        index = 10    rs_spec(index).s = 0.16    rs_spec(index).T = 5        rspara.UserDefinedTable = rs_spec    rspara.Comment = "test rs"    rspara.DefinitionType = ResponseSpectraType.UserDefinedRS    rspara.description = "test rs via COM"    rspara.Number = rs_no        iDynCase.SetRSParams rs_no, rspara    e:  If Err.Number <> 0 Then MsgBox Err.description, , Err.Source        iMod.GetApplication.UnlockLicense    Set iMod = Nothing    Set iApp = Nothing

The response spectrum was created according to EN 1998‑1:2010 and has 11 points. First, an array of the RSTableRow type with 11 elements was created, filled with data, and then saved under the UserDefinedTable property. The transfer is carried out using the SetRSParams command.

• ### Is there any feature for a quick generation of a girder grillage or a grid?

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Yes, you can quickly create surfaces, grids, or girder grillages by extruding lines and members. However, if you want to generate an irregular grid with extended specifications, the Generate Grid dialog box is recommended.

In our case, we would like to create a regular grid by using the Extrude Member into Grid function.

In the Extrude Member into Grid dialog box, you can specify various settings.

As a result, we obtain the desired grid and can thus continue modeling.

• ### I have edited the material in my model. When starting the calculation, I get an error message. What can be the reason for this?

Materials are required to define surfaces, cross-sections, and solids. The material properties affect the stiffnesses of these objects.

There are 13 material models available if you have a license for the RF‑MAT NL add-on module.

In the case of the abundance of material models, it is necessary to make sure that you assign the corresponding material model to the members and their surfaces/solids.

In the example shown here, surfaces have been generated from a member for a detailed analysis. There is still an unused cross-section defined (marked in blue) and the material is entered for the member cross-section as well as for the surfaces. When editing an existing material to Isotropic Nonlinear Elastic 2D/3D , the 2D/3D material model is also defined for the created member cross-section, which leads to the error message.

When working with members and surfaces / solids, it is recommended to create more than one material.

• ### How can I delete a load case in the Project Navigator?

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You can delete the selected load cases in the navigator as follows:

1. Activate the "Data" tab in the Project Navigator.
2. Select the load cases to be deleted under "Load Cases and Combinations" → "Load Cases."
3. Right-click the selection and select "Delete."
• ### Is it possible to combine several load cases in one load case?

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You can combine several load cases into one load case by right-clicking the existing load case and using the "Add Load Cases..." option.

A dialog box appears where you can select the load case in which you want to add this load.

This procedure can be used to combine loads from several load cases in one load case.

• ### How can I consider eccentric load introduction for surfaces?

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In this regard, there are several options.

On the one hand, you can decompose the eccentric load into the vertical component and the moment component, and model the loading by using line loads.

On the other hand, you can apply the line load eccentrically to the surface by means of an additional surface with the surface type - Stiffness "Rigid."

• ### How can I quickly transfer a load from one load case to another? I have entered my loads into an incorrect load case by mistake.

A load that was accidentally applied in the wrong load case can be copied from one load case to another by using the table with the area "3. Loads."

In the table, select the type of load that you want to transfer from one load case to another. In the subsequent graphic, these are the "member loads," for example. Then, select and right-click the row describing this load. A shortcut menu appears where you can select "Copy." As an alternative, you can use the keyboard shortcut "Ctrl + C" directly after selecting the row.

After copying the row to the clipboard, you can switch to the "Target load case" in the table area and paste the entry from the clipboard using "Ctrl + V."

Note: This procedure is not possible for the generated loads.

• ### In the manual, there is a dialog box that shows six options: Load Cases, Actions, Combination Expressions, Action Combinations, Load Combinations, Result Combinations. However, I have only three options for selection. How do I get the six options displayed?

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If load cases are superimposed manually, the "Edit Load Cases and Combinations" dialog box only provides three options. This is specified in the "General Data" dialog box.

If you select the "Create combinations automatically" check box, you obtain the additional options (actions, combination expressions, action combinations) as desired.

• ### How can I adjust the wind tunnel to the model in RWIND Simulation?

If the model is not placed correctly in the wind tunnel, you can use the "Adjust to Model" function in the wind tunnel properties to place the wind tunnel around the model properly.

In this step, the function arranges the wind tunnel floor at the bottom of the model and places the remaining wind tunnel sides next to the model with a usual distance depending on the model dimension.

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#### First Steps

We provide hints and tips to help you get started with the main programs RFEM and RSTAB.

#### Wind Simulation & Wind Load Generation

With the stand-alone program RWIND Simulation, wind flows around simple or complex structures can be simulated by means of a digital wind tunnel.

The generated wind loads acting on these objects can be imported to RFEM or RSTAB.

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