#### Further Information

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• ### RFEM shows a warning message about an intersection that is not defined correctly. How can I avoid this?

New FAQ 004335 EN

The reason for this warning might be overlapping surfaces, which can occur when for example one solid is modeled onto another, see figure 1.

In order to avoid overlapping surfaces, an opening is required here. After defining that opening, also check if the definition of the solids have to be corrected.

• ### In RWIND Simulation, I want to rotate the model, adjust the wind tunnel, and then rotate the model again. How can I prevent the rotation point of the model from being changed?

New FAQ 004332 EN

In RWIND Simulation, it is possible to adjust the model position and the model rotation manually. To do this, simply select Model → Edit in the navigator and then the desired rotation angle in the Position tab. In this case, the rotation is carried out without changing a displacement.
• ### Problems occur when generating the FE mesh of an ETFE cushion. I cannot find the error. What can I do?

New FAQ 004329 EN

In most cases, the problem is that in the edge area of the cushion, the finite elements of the cover surfaces are very close to each other when Bezier surfaces have been used. The FE mesh nodes of the bottom and top surface may then be combined. The FE mesh nodes of the bottom and top surface may then be combined.

1. Numerical correction of the problem:

You can adjust the tolerance for combining FE mesh nodes via the menu 'Tools' → 'Regenerate model'.

2. Solving the problem geometrically:

The more reasonable solution is to increase the distance between surfaces by edge surfaces, as shown in Figure 01.
• ### How can I create a comment via the COM interface?

New FAQ 004326 EN

When using the COM interface (RS-COM or RF-COM), it is possible to create a comment through the guide object interface (IGuideObjects). The following is an example program that sets a comment:

Sub test_comment()'   get interface from the opened model and lock the licence/program    Dim iModel As RFEM5.IModel3    Set iModel = GetObject(, "RFEM5.Model")    iModel.GetApplication.LockLicenseOn Error GoTo e        Dim iModelData As RFEM5.IModelData2    Set iModelData = iModel.GetModelData        Dim iGuiObj As RFEM5.IGuideObjects    Set iGuiObj = iModel.GetGuideObjects        Dim comm As RFEM5.Comment        '   set frame type    comm.Frame = CircularFrameType        '   set reference object type    comm.ObjectType = GeneralObjectType    comm.ObjectNo = 1        '   set point if GeneralObjectType is choosen    comm.Point.X = 2    comm.Point.Y = 4    comm.Point.Z = 6        '   set offset from reference object    comm.Offset.X = 0.5    comm.Offset.Y = 1    comm.Offset.Z = 1.5    comm.Rotation = 1        '   set text of comment    comm.Text = "testcomment"        '   transfer object to program    iGuiObj.PrepareModification    iGuiObj.SetComment comm    iGuiObj.FinishModification    e:  If Err.Number <> 0 Then MsgBox Err.description, , Err.Source        Set iModelData = Nothing    iModel.GetApplication.UnlockLicense    Set iModel = NothingEnd Sub

The selection of the reference or the element to which the comment is considered to be attached to is first defined by the type (ObjectType). Here, it is possible to select e.g. a member, a node or any point in space. Next, the number of the reference object is specified via ObjectNo (e.g. member 1). If a free point has been selected, it is set by Point.
Finally, an offset can be specified, which results from the reference object.
• ### Does it make a difference if I model a floor-level downstand beam as a ‘Rib’ or as a ‘Result Beam’?

New FAQ 004323 EN

Yes, it makes because this affects the stiffness of the entire system.

When entering a level-floor downstand beam as a ‘Rib’, you will add the stiffness of the defined rectangular cross-section to the area of the line.

For the result beam, however, you have only to define the integration width. The entered rectangular cross-section does not influence the stiffness of the entire system but is only applied as a design cross-section in the add-on modules (e.g. RF-CONCRETE Members).

• ### I would like to model a threaded bar as a 3D solid in RFEM. Is this possible?

New FAQ 004322 EN

A thread cannot be created using a function in the program. In such a case, you have to create this geometrically via nodes and lines. In the program, there is an option to create the windings through trajectory surfaces. However, you have the option to reach your target relatively quickly when using Copy and Rotate.
• ### Is it possible to connect a rib member to two surfaces with different thicknesses? And where can I check the cross-section properties of this composite cross-section? In RFEM, I can only see the eccentric rectangular profile and its cross-section properties.

New FAQ 004318 EN

You can connect a rib member to a line on two surfaces with different thicknesses.

To determine the stiffness or internal forces, the eccentricity of the rectangular cross-section is determined using the mean value of both connected surfaces in RFEM.

For designing in RF-CONCRETE Members, the add-on module determines its cross-section, which is displayed in the input dialog box ‘1.4 Ribs’ of the add-on module.

By clicking the ‘i’ button (see Figure 02), it is possible to open an info dialog box for the generated rib cross-section, where all cross-section properties applied for the design in the module, like the position of the shear center and centroid, etc., can be viewed.

If the ‘Effective Width’ is adjusted in the ‘1.4 Ribs’ dialog box (e.g. to 0.50 m) this has influences on the cross-section applied in RF-CONCRETE Members and its cross-section properties.

However, this does not influence the stiffness or the determination of internal forces in the 3D model in RFEM.

• ### I have a structure with many members. How can I quickly find a member by member number?

FAQ 004276 EN

The easiest way to find a member is to select Project Navigator - Data. Here, right-click the members and select "Find Members." Now you can enter the member number and the member is marked with an arrow in the graphic.
• ### I have simulated a bored pile using a member and now I want to simulate the surface friction with a member foundation. Can I also enter this member elastic foundation linearly variable via the height?

FAQ 004272 EN

No, this is not possible.

The member elastic foundation is basically constant over the length of the member.

If you want to enter a variable member foundation based on the height of the bored pile, you have to divide the bored pile into individual members and specify different constant foundations on the individual members. Thus, the linear distribution of a foundation can be approximately simulated.

• ### How can I move a member or a line by Drag & Drop?

FAQ 004268 EN

The drag & drop function is very helpful for fast work in RSTAB and RFEM. This option must first be activated in the shortcut menu (Figure 01).

If you click a member or a line near the start or end node in the work window, you can quickly define the new connection point graphically.

However, if you grab a member or a line in the middle third, you can simply move the element to a new position.

If you additionally press the 'Ctrl' key, the marked elements are copied.

The video first shows how to move the column head of member 2 from node 2 to node 4. Then it is shown how the member 2 is moved to a new position.

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If not, contact us via our free e-mail, chat, or forum support, or send us your question via the online form.

#### 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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