# Frequently Asked Questions (FAQ)

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• ### A curved pane cannot be designed in RF‑GLASS. Why?

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When modeling a glass pane, especially an insulating glass pane, it is necessary in RFEM to pay special attention to the boundary lines that must consist of four lines only.
If possible, you should avoid the division of lines since the calculation cannot be performed anymore. In that case, the corresponding warning message will be displayed before the calculation.
If special intermediate nodes are required on the line, make sure that they do not divide the original line when creating them.
However, if the line is divided anyhow the structure can be restored by using the "Delete Node and Merge Joined Members" command.
In exceptional cases, you can deactivate using the layered mesh in the details of the composition. This option has been specifically implemented for double-curved panes.
• ### In the model, there are two governing internal forces, Vz and My. In the printout report selection, I have only activated these two internal forces with the 'Extreme Values' option. Why are duplicate result lines displayed in the report in 'Members - Internal Forces'?

In this case, the reason for four result lines (see Fig. 01) is that a minimum and a maximum including the associated remaining internal forces are output for each selected internal force.

• First line: Numerical maximum of Vz (3.54 kN) with corresponding internal forces
• Second line: Numerical minimum of Vz (0 kN) with the corresponding internal forces
• Third line: Numerical maximum of My (0 kNm) with corresponding internal forces
• Fourth line: Numerical minimum of My (-12.37 kNm) with corresponding internal forces

• ### How can I create an intersection point between a line and a surface?

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The intersection between surfaces and lines can be created with the "Connect Lines/Members" function. To do this, select the "Connect Lines/Members" function and then draw a window over the elements to be intersected (Figure 01). A node will be created at the intersection point. This is also shown in the video.
• ### How can I transfer a field of nodes instead of just a single node via the COM interface in VBA?

To transfer several elements, you have to create a field (array) in VBA first:

Dim nodes(0 to 2) as RFEM5.Node

Then, you can use the method IModelData.SetNodes() to transfer all nodes to the field (here, three elements 0,1,2) at once.

These methods are also available for the following structural elements, for example:

IModelData.SetLines()IModelData.SetMembers()IModelData.SetSurfaces()
• ### Is there an easy way to create a spatial structure from a 2D model, whereby the nodes in columns and lines will be extruded into walls?

For lines, this option is already available directly in the shortcut menu. For extruding nodes into members and lines in surfaces, there is the corresponding option in the detailed settings of Copy/Rotate/Mirror. As soon as at least one copy is generated, the new elements will also be created.
In case this feature is not wanted anymore, it should be deactivated in the detailed settings again.
• ### I have a model with a segmented curved layout of the line. How can I create a single line from it?

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First, it is necessary to remove the individual lines because it is not possible to merge the partial lines into an overall line. If only a few nodes are available, they can be selected one after the other for the line definition. To ensure that the selection with a selected area works in the case of a structural system with many nodes, it is important that the numbering is continuously increasing or decreasing. If necessary, you can carry out the automatic numbering.
• ### I get the warning No. 469 "Lines [line numbers] lying in the surface intersect each other and share no common node." If I confirm the warning with "No," the error No. 639 appears: "Error No. 11 while generating the FE mesh!". What can I do?

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The intersection of the lines mentioned in the warning must be created using the "Connect Lines/ Members" function. To do this, select the "Connect Lines/ Members" function and then draw the window across the elements to be intersected (see Figure 03).

In many cases, stiffening bracings are modeled in the same plane as the surface, and the members are subsequently set eccentrically. Please keep in mind that the lines and thus the members are automatically integrated into the surface. Since the stiffening brace should usually only transfer axial forces, it is recommended to remove it from the surfaces to avoid creating a bond between the surface and the member. To do this, remove the corresponding lines from the surface in the "Integrated" tab (see Figure 04).
• ### I would like to export a result using isolines or isosurfaces and read them in later. Is that possible?

Yes, it works. You have to display the corresponding graphic and activate the export function. To do this, first select the format ASCII format - results. The tab "Results - Isolines / Isosurfaces (.dxf)" can be used to select the respective elements to be exported (see Figure 1).

Via the import function of the program, this dxf-file can be downloaded eg For example, you can import it into an existing model as a background slide (see Figure 2).

• ### Is it possible to reconnect shared lines or members?

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It depends on the initial situation. Currently, lines and members can only be rejoined or combined if no other elements are connected to the division nodes. This is illustrated in the attached figure.

To combine the multiply divided member, select the intermediate nodes. Then, click "Delete Node ->." In the shortcut menu
This function is not available for the lower part of the structure because merging would delete the definition node of the connected beam.
• ### Why do I not receive a color scale in the panel despite the available results?

To display the color scale, make the following settings:

• For member results: Activates the option "Colored with gradient", "Colored without gradient" or "Cross-Sections" under "Results" → "Members" in the Display navigator, see Figure 1

• For surface results: Activation of the option "Isobands," "Iso- lines" or "Differences" under "Results" → "Display Type", see Figure 1
• For member and surface results: Select all or selected members / surfaces within the "Filters" tab in the panel, see Figure 2

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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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