#### Further Information

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• ### I would like to divide a line very finely, but I can only define the minimum of 0.5 mm with the "Divide Line → Distance" feature. How can I avoid the problem?

The "Divide Line → Distance" option has the fixed minimum limit of 0.50 mm. If you want to shorten the line (for example, 0.25 mm), divide it to 1.00 mm first. Then, you can use the "Divide Line → n Intermediate Nodes" function to generate three intermediate nodes. Thus, you will get the line length of 0.25 mm.

###### Important!
One of each file unites the adjacent nodes that are closer together than 0.5 mm. In the case mentioned above, this has to be adjusted by means of the "Tools → Regenerate Model" feature (see Figure 02).
• ### 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 use the load generator "Convert Area Loads to Member Loads via Cells." What is the function of the "Nodes on virtual lines" feature?

If a cell closed on all sides is detected in the structural model, it can be used for the load application. However, if the desired load range is not completely enclosed by members, the cell is not recognized by the load generator.

The "Nodes on virtual lines" function allows you to define the corner nodes of the load area manually, and thus clearly define the cell area. The cell defined in this way can then be selected as usual by using the pick function of the individual cell nodes.

• ### I get the error message 30420 saying that the tolerance (epsilon) for integration of a node into a line is too large. What can I do?

The tolerance epsilon can be found in the FE mesh settings in the "General" section of the dialog box. It controls the behavior of the FE mesh generator when nodes are very close to lines. Figure 03 shows the difference. If the tolerance is greater than the distance of a node to a line, this small local difference in the mesh generation is neglected. In the case shown, the mesh of the line is deflected towards the node. In this case, the line is not ideally straight anymore. If the tolerance is smaller than the distance, a separate FE node is generated for the node.

The error message appears if the distance between two adjacent nodes is smaller than epsilon and they are connected by a line (see Figure 03). In most cases, this is due to an inaccuracy in the modeling. Since the error message contains no information about the node numbers, you can use the "Identical Nodes" model check. The program searches for the nodes whose distance meets the tolerance delta. Now, you can set the tolerance value to the value of epsilon. Tthe nodes are then listed in the upper part of the dialog box.

As described below, the descriptions differ depending on the case. If there is an inaccuracy in the modeling, it can be adjusted. In other cases, it is possible to further reduce the tolerance of epsilon, of course.

The form-finding process in RFEM searches for a shape that is in equilibrium with the boundary reactions for the members depending on the defined force or geometry parameters and for the surfaces depending on the defined force parameters.

If further force effects occur in addition to these element-related form finding properties, such as the dead load of the elements or the weight of the cable node connections, it is necessary to define these loads in an additional load case with the "Form-Finding" action category.

The form-finding process recognizes these special load cases by their action category and in addition to the element-related form-finding information, it applies all loads from all load cases with the "Form-Finding" action category in the analysis when the searching for the shape.

Since the loads are applied to the model in the load cases with the "Form-Finding" action category in the form-finding process, a separate analysis of these load cases is of no importance. These load cases are only used for the initial entry for the form-finding process.
• ### After importing a .stp file, there is a free node near each member. Why are these nodes created?

The trigger for this is due to the member rotation of a member. A member rotation can be defined in RFEM and RSTAB using two options:

• Option 1: Rotation via angle
• Option 2: Rotation via help node

These options can be specified in the detail settings for the import of the .stp file. If the function shown in Figure 02 is activated, the first option with the angle is used. If you deactivate this function, a help node is created automatically with which the member rotation is defined.
• ### Why can I not create any dimensions? I can't snap any nodes or members. Points and nodes are not snapped.

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At the bottom of the user interface of RSTAB and RFEM is the status bar. The center area can be used to influence the user interface. If the options FANG and OFANG are activated, grid points, nodes and objects can be caught (see Figure 1). Then a dimensioning of the system is possible.
• ### After the calculation, I get displayed only the maximum result value for the deformations. Can I display all nodal deformities as well?

To also display the desired nodal values, select the "Nodal displacements" option in the Display navigator (see figure).
• ### Is it possible to divide a line or a member?

You can divide lines and members by right-clicking the object and then selecting "Divide Line" or "Divide Member" in the shortcut menu.

The shortcut menu offers three different division options, see Figure.

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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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