Frequently Asked Questions (FAQ) - Search term: Display l...

Yes, you can. Move your mouse pointer over the node and wait a moment. A bubble with the node coordinates will appear.

You can hide the undeformed geometry in the Display tab of the navigator by deactivating the Model check box:

The following programs and add-ons are particularly suitable for structural timber projects.

Main Program

To model your structure and determine the internal forces, you need one of the main programs. Depending on the application area, you can use RFEM 6 or RSTAB 9.

• RSTAB: Analysis of planar or spatial frame & truss structures
• RFEM: Finite element analysis of plate, wall, shell, and member structures

If your model has surface components, such as plates and walls, in addition to membe elements, you need RFEM. This program is the only one with the capability to analyze laminate or cross-laminated timber elements and curved objects.

Timber Design Add-on

Use the Timber Design add-on to design the timber components of your model. The design checks in compliance with specific standards cover both members (bending beams, columns) and surfaces (plates, walls). For columns, the stability analysis according to the equivalent member method or the second order analysis is performed.

You can perform the ultimate and serviceability limit state design checks, as well as the fire resistance design according to the following standards:

• EN 1995 – including National Annexes
• SIA 265
• NTC
• NDS
• CSA O86
• GB 50005
• AS 1720

In the fire resistance design, the charring of a cross-section is taken into account for both the stiffness and the design.

Multilayer Surfaces Add-On

With the Multilayer Surfaces add-on for RFEM, you can analyze laminate and sandwich structures with user-defined layer structures. This allows you to design cross-laminated timber panels, for example.

If certain layers have nonlinear material behavior, you can assign the appropriate properties to them. Furthermore, this add-on allows provides you with the option to analyze curved surfaces.

Additional Add-ons

In case of special requirements for your timber structure, we recommend further add-ons and additional programs to help you solve the task.

If you need to perform seismic or vibration analysis, the dynamic analysis add-ons provide you with powerful tools for your structural analysis and design. The Modal Analysis add-on enables the calculation of natural frequencies, and in combination with the Response Spectrum Analysis add-on, you can also perform seismic analysis according to numerous standards.

If you are designing a building with a complicated shape, so that the determination of wind loads according to the relevant standards reaches its limits, the RWIND RWIND program will help you: Using a CFD analysis, you can determine the wind loads even for highly complex building shapes.

If the construction stages affect the final internal forces in a structure, or if the governing internal forces for the structural design result from certain construction stages, you should consider the modeling using the Construction Stages Analysis add-on. The Building Model add-on allows you to easily enter large multi-story timber structures.

If you receive an RFEM 6 or RSTAB 9 file for further processing, the structures will be displayed in the program using the display settings of the last editor.

If this display does not meet your own requirements, you can simply right-click the free area of the Navigator – Display and select "Dlubal Standard". This returns the settings to the default values.

Please note that the enveloping results are usually shown when displaying the results of design situations or result combinations.

There are three options to graphically display the results of deformations, internal forces, and support forces: Max and Min-values can be displayed separately. To display both envelopes from the extreme values on the model, select Max and Min-values.

In order to specify a uniaxial load transfer for a plate, you can assign orthotropic properties to the surface. This way, you can control the stiffnesses for specific directions so that the loads are mainly transferred in one direction. You have two options.

Orthotropic Thickness for Isotropic Material

• Double-click the surface to open the dialog box for editing the slab.
• In the Thickness with Material section, click the button to the right, to create a new thickness.
• In the "New Thickness" dialog box, select the Shape Orthotropy thickness type.

• Switch to the "Shape Orthotropy" tab. The Effective Thicknesses orthotropy type is set by default.
• For the uniaxial load transfer, enter the effective thicknesses as orthotropic properties in such a way that the stiffness is very high in the desired main support direction and very low in the other direction.

• To consider the self-weight, you can apply a user-defined fictitious thickness that corresponds to the full surface thickness.
• Click OK to save the thickness.
• Click OK again in the "Edit Surface" dialog box to assign the thickness to the plate.

Orthotropic Material Model for Constant Thickness

• Double-click the surface to open the dialog box for editing the slab.
• In the Thickness with Material section, click the button to the right, to create a new material.
• In the "New Material" dialog box, select the material from the library as usual. However, change the material model to Orthotropic | Linear Elastic (Surfaces) (1). Also, activate the User-defined material option (2).

• Switch to the "Orthotropic | Linear Elastic (Surfaces)" tab.
• For a uniaxial load transfer, change the modulus of elasticity of the secondary load direction to a very small value. You can also specify very small values for the shear moduli in the secondary support direction. Furthermore, set the Poisson's ratios to zero.

• Click OK to save the material.
• Click OK again in the 'Edit Surface' dialog box to assign the material of the plate.

If a Rhino surface cannot be created by using the geometry type, it will not be transferred. This is the case, for example, of curved surfaces with more than four boundary lines. In the Rhino command history (_CommandHistory or the F2 key combination), you can find a list of warnings and errors displayed during the transfer process:

In RFEM and RSTAB, you can hide certain objects and thus create user-defined visibilities. These hidden objects are displayed in gray in the background.
The intensity of the gray color can be adjusted in the "Program Options & Settings" dialog box under the "Settings" tab.

You can select a value between 0 and 1. The higher the selected value, the darker the inactive objects are displayed.

The following programs and add-ons are perfectly suitable for your reinforced concrete projects.

Main Program

To model your structure and determine the internal forces, you need one of the main programs. Depending on the application area, you can use RFEM 6 or RSTAB 9.

• RSTAB: Analysis of planar or spatial frame & truss structures
• RFEM: Finite element analysis of plate, wall, shell, and member structures

If your model has surface components, such as plates and walls, in addition to membe elements, you need RFEM.

Concrete Design Add-on

Use the Concrete Design add-on to design the reinforced concrete components of your model. The design checks according to specific standard include not only members (bending beams, columns) and surfaces (plates, walls), but also surfaces susceptible to punching shear. For columns, the stability analysis according to the nominal curvature method is integrated in the add-on.

You can specify user-defined reinforcement or determine it by using the program. With these basic conditions, you can perform the ultimate and serviceability limit state design checks according to one of the following standards:

• EN 1992, including National Annexes
• ACI 318
• CSA A23.3
• SP 63.13330

The add-on also allows for deformation analyses for cracked reinforced concrete surfaces (state II) using the approximation methods described in the standards. Tension stiffening as well as creep and shrinkage can be taken into account.

Additional Add-ons

If you have special requirements for the reinforced concrete structure, we recommend further add-ons and additional programs to help you solve the task.

To use a cross-section that is not included in the extensive cross-section library of RFEM 6 or RSTAB 9, the RSECTION program helps you when modeling the cross-section including reinforcement. You can then design this cross-section as usual in the Concrete Design add-on.

If you need to perform seismic or vibration analysis, the dynamic analysis add-ons provide you with powerful tools for your structural analysis and design. The Modal Analysis add-on enables the calculation of natural frequencies, and in combination with the Response Spectrum Analysis add-on, you can also perform seismic analysis according to numerous standards.

If you are designing a building with a complicated shape, so that the determination of wind loads according to the relevant standards reaches its limits, the RWIND RWIND program will help you: Using a CFD analysis, you can determine the wind loads even for highly complex building shapes.

If the construction stages affect the final internal forces in a structure, or if the governing internal forces for the structural design result from certain construction stages, you should consider the modeling using the Construction Stages Analysis add-on. The Building Model add-on allows you to easily enter large multi-story concrete structures.

Basic Add-ons

If you design steel structures, you need the following add-ons in addition to RFEM or RSTAB:

• Steel Design
• Stress-Strain Analysis
• Stability
• Steel Joints

The Steel Design add-on allows you to perform stability analysis (lateral-torsional and torsional-flexural buckling) in addition to the normal cross-section design.

The Stress-Strain Analysis add-on calculates not only stresses, but also strains in members, surfaces, and solids.

Steel structures are usually slender structures so the stability plays an important role. Use Structure Stability add-on to calculate the effective lengths and critical load factors for a precise stability analysis.

Model the connections between members precisely and flexibly using the Steel Joints add-on that is based on FEA. The connections need to be loaded not only in the main load-bearing plane. Even if the connection is loaded about the "minor axis", you can dimension the connection using this add-on.

Additional Add-ons

If you have special requirements for steel design checks, there are other add-ons and additional programs available to support you in solving your special tasks.

To use a cross-section that is not included in the extensive cross-section library of RFEM 6 or RSTAB 9, the RSECTION program helps you when modeling the cross-section and calculating the section properties.

If you want to analyze the lateral-torsional buckling with the more accurate and cost-effective method with 7 degrees of freedom, you will need the Torsional Warping (7 DOF) add-on.

If it is necessary to consider the plastification of the material when determining the internal forces, you can use Nonlinear Material Behavior add-on.

The Modal Analysis add-on enables the calculation of natural frequencies, and in combination with the Response Spectrum Analysis add-on, you can also perform seismic analysis according to numerous standards.

If you are designing a building with a complicated shape, so that the wind load calculation according to the relevant standards reaches its limits, then the RWIND program will help you: Using a CFD analysis, it can determine wind loads even for the most complicated building shapes.

If the construction stages affect the final internal forces in a structure, or if the governing internal forces for the structural design result from certain construction stages, you can model this using the Construction Stages Analysis add-on.

The Building Model add-on allows you to easily enter large multi-story concrete structures.

For your design of lightweight steel structures, containing cables and membranes, the Form-Finding add-on can help you to determine the shape of the structure.

Both features known from RFEM 5, "Area Load on Members via Planes" and "Area Load on Members via Cells", can be found in RFEM 6 in the load wizard "Member Loads from Area Load". You can either define planes via nodes (marked in green in the image) or select the cells (marked in blue in the image).

If you display a visibility—as described in the manual chapter Visibilities—the inactive objects are also displayed with a reduced intensity.

To hide these inactive objects completely, deactivate the Show Hidden Objects in Background checkbox in the General category of the "Navigator – Display".

Saving Graphic Template

Once you have assigned the concrete material and activated the design properties in the member input dialog box, the display of the reinforcement layout for the selected member is available.

In the Display Reinforcement Layout window, you can proceed as follows.
1. Use the options in the menu bar to customize the display according to your preferences.
2. This configuration can send "Directly to a printer" as a template.
3. When saving the template, it is stored globally and is also available for future models.

Multi Print of Reinforcement Layout for Selected Members

Use this graphic template to print the reinforcement of any members with a similarly formatted reinforcement layout in a multi print.

First, it is worth taking a look at the "Load Transfer" tab when editing the surface. If the load transfer direction is set to "Isotropic | FEM", the loads are not displayed until the load case or load combination has been calculated, as they must be calculated in a sub-model first. So make sure the results are available there.

When creating a new model in RFEM, it is not possible to import the templates from any path. It is necessary to create a project.

When accessing a template in Revit or Rhino/Grasshopper, an error message often appears if the path of the template file used is not linked to a "Template Project" in the Dlubal Center.

Open the Dlubal Center and check whether there is a "template project" for the folder with your template file.

If not, you can add the path of the template file as a project. In the FAQ video, the Downloads folder has been created as a template project, as it contains the template file.

Using the cross-section library, it is possible to display the unit stresses at the individual stress points of cross-sections. If you know the internal forces of the respective cross-section, you can quickly find a suitable cross-section without starting the stress calculation of the entire model.

The choice between steady-state (by using RWIND Basic) and transient simulation (by using RWIND Pro) depends on the specific requirements of the wind analysis, the level of accuracy needed, and the computational resources available. Steady-state simulations are suitable for simpler, time-invariant analyses, while transient simulations are necessary for capturing the dynamic behavior of wind flow and its impact on structures over time, and are more accurate than steady-state simulation.

Parapets present a unique challenge in the analysis of wind loads on buildings due to their positioning and the complex flow patterns they generate. Their interaction with wind loads is influenced by several factors that contribute to their complicated behavior:

Height and Exposure

Parapets extend above the main roof level, exposing them to higher wind velocities and different flow patterns compared to lower parts of the building. This exposure means they can experience significantly different wind pressures, including uplift forces.

Geometry and Shape

The shape of the parapet—whether it is flat, crenellated, or has other architectural features—can affect how wind flows over and around it, leading to complex patterns of vortices and turbulence. These flow patterns can alter the distribution and magnitude of wind pressures on the parapet and adjacent roof areas.

Interaction with Building Shape

The overall shape of the building influences how wind flows around it, which in turn affects the wind loads on the parapet. For instance, wind flowing over a streamlined, aerodynamic building will behave differently from wind encountering a building with a more bluff body. This interaction can lead to areas of higher pressure or suction on the parapet that are difficult to predict without detailed analysis.

Vortex Shedding

Tall parapets on high-rise buildings can experience vortex shedding, where alternating vortices are shed from either side of the parapet, leading to oscillating pressures that can cause structural vibrations. These effects are highly dependent on the wind speed, parapet shape, and the building’s orientation to the wind.

Gust Effect

Parapets can be subjected to gusting effects, where short-duration increases in wind speed cause fluctuating loads. These transient effects are particularly important for the structural design of parapets to ensure they can withstand sudden wind load increases without failure.

Given these complexities, advanced simulation techniques such as computational fluid dynamics (CFD) are often employed to accurately predict the wind loads on parapets. Both steady-state and transient simulations play a role, but transient simulations provide a more detailed understanding of how parapets respond to varying wind conditions over time in RWIND 2 Pro. These simulations can capture the instantaneous effects of gusts, the development of vortices, and the impact of turbulent flow, which are critical for designing parapets to be both functional and safe under wind loading.

In the RSECTION program, you can analyze general steel or aluminum cross-sections and determine the effective section properties. For this, you need the Effective Sections program extension of RSECTION. If you have licensed this add-on, you can activate the Effective Section option for the calculation in the Base Data of the cross-section.

Then, define the standard according to which the calculation should be performed. Currently, the following options are available:

• EN 1993-1-1 and EN 1993-1-5
• EN 1993-1-3 (Cold Formed)
• EN 1999-1-1 (Aluminum)

The effective section properties depend on the internal forces of the cross-section. Therefore, create a load case and define one or more internal force constellations.

After the calculation, the effective section properties are displayed in the table. In the graphic, you can check the stresses on the effective section.

Once you have saved the cross-section, you can import it into RFEM or RSTAB to use it for further analyses.

The webinar Determination of Section Properties and Stress Analysis in RSECTION shows the modeling and calculation of a cold-formed section. You can find further information there.

Both RFEM and RSTAB are available for the structural analysis and design of temporary structures, such as carousels, roller coasters, stages, or grandstands. There are add-ons available for both main programs that you can use to design steel, aluminum and lightweight structures according to various standards. If you also want to analyze membrane and cable structures, RFEM is your tool of choice.

Main Programs RFEM and RSTAB

The main programs RFEM and RSTAB are used to define the model with its properties and actions. RFEM proves to be the more versatile option, as it can be used to analyze structures with surface components, such as membranes, in addition to pure member structures.

Available Standards

For the design of steel beam and cable structures, the following standards are available:

• EN 1993 (Eurocode 3)
• BS 5950 (British standard)
• AISC 360 (US standard)
• SIA 263 (Swiss standard)
• IS 800 (Indian standard)
• GB 50017 (Chinese standard)
• CSA S16 (Canadian standard)
• AS 4100 (Australian standard)
• NBR 8800 (Brazilian standard)
• SP 16.13330 (Russian standard)

Aluminum structures can be designed according to the following standards:

• EN 1999 (Eurocode 9)
• ADM (US standard)
• GB 50429 (Chinese standard)

Analysis and Design Add-ons

Design add-ons supplement the functionality of the main programs. In the design add-ons Steel Design and Aluminum Design, you can perform the ultimate and serviceability limit state design, as well as the stability analysis according to the standards listed above.

In the case of membrane and cable structures, the Form-Finding add-on facilitates your task to determine the shape of member and surface models subjected to axial forces. On the other hand, you can use the RWIND program to perform simulations in the digital wind tunnel for complex structures and to transfer the generated wind loads to RFEM.

Dynamic Analysis

If you need to perform a seismic or vibration analysis, the corresponding Dynamic Analysis add-ons are the perfect tools for determining natural frequencies and mode shapes, or for the analysis of external excitations.

In case of any questions about the Dlubal solution for temporary structures, our sales team will be happy to assist you.

The Form-Finding add-on is available for the structural FEA software RFEM, which you can use to search for the shape of a tensile membrane structure before the actual design.

Once you have modeled a supporting structure or a substructure in RFEM and defined membrane surfaces, you can analyze the global model according to the large deformation analysis.

Programs and Add-ons

Use the main program RFEM to define the model, including the properties and actions.

The Form-Finding add-on allows you to determine a shape of the member and surface models subjected to axial forces.

Use the RWIND program to perform simulations in the digital wind tunnel for complex structures and to transfer the generated wind loads to RFEM.

Depending on the design, you can use the add-ons Steel Design and Aluminum Design to design the structure.

If a seismic or vibration analysis is required, the Dynamic Analysis add-ons are the perfect tools for this.

In case of any questions about the Dlubal solution for tensile membrane structures, our sales team will be happy to assist you.

Since the AI assistant Mia has entered the Dlubal website, you now have direct access to fast support 24 hours a day, seven days a week.

The chat window is located at the bottom right of the Dlubal website; see Image 02.

If Mia is not displayed in your browser, you have probably not approved the use of cookies. They are required to allow the participation in the chat; see also Image 03.

Note

If you have any questions for Mia, please also specify the product you would like to know more about.
Restricting the version number, for example RFEM 5 or RFEM 6, helps you and Mia to quickly find more precise answers.
If you have questions about the login, it is also important whether you want to log in to RSTAB 9 or the Dlubal Extranet.

Try it out. Test Mia yourself and get excited.

In order to evaluate user-defined points in addition to the result values on grid points and FE mesh nodes, there is the option to specify "Additional Surface Result Points" in RFEM 6. You can find them under "Types for Surfaces", as shown in Image 01.

The coordinates for these points are entered directly in the dialog box or selected in the model; see Image 02. Furthermore, it is necessary to assign the surface whose result values should be displayed.

In the Results navigator (the upper half), you can activate and deactivate the display of the manually specified result values. In the lower half of the Results navigator, you can set the display for grid points and/or surface result points; see Image 03.

When displaying the values in FE mesh points, the additional surface result points are deactivated.

For the Isotropic load transfer (LT) surface, RFEM uses the finite element method and creates a submodel. In the FEA submodel, the LT surface is substituted by a rigid surface where all the structural elements that are integrated in the surface are substituted by rigid supports. In a future implementation, users will have the ability to adjust the support conditions. The support reactions in the FEA submodel are then converted into member loads after running the calculation.

To display the load separately as member loads after running the calculation, activate the "Loads from Distribution Surface" option in the Display Navigator.

For the data exchange between RFEM and other programs (for example, Revit, Tekla, Grasshopper), it is necessary to specify the full Dlubal material or section name. Thus, the denotation and the corresponding standard can be clearly assigned in the Dlubal material and cross-section library.

You can open the complete material or section names by using the Open Conversion Tables function in the CAD-BIM menu of RFEM.

The Dlubal material and cross-section denotation can be taken from these tables for the relevant conversion.

If the material and cross-section descriptions are to be imported from an existing model, it is possible to display the full name for cross-sections and material using the program options.

Yes, it is.
To deactivate the blue/red colors in the result tables, click the "View" menu of the tables, and press the "Display Color Scale" button. You can also use the corresponding button in the table toolbar.

For the printout report, you can also deactivate the "Color Scale" option in the "Printer and Page Settings" dialog box in the "Other Settings" tab.

This can be quickly done by activating the nodes with support (1) in the Navigator – Views, and displaying the associated supports (2).

Then, you can activate the numbering (menu "View" → "Display Numbering").

For open structures that consist only of members, such as lattice towers, the load acts only on the member cross-sections.

To apply area loads such as snow or wind to an open structure, select Load Wizards → Member Loads from Area load to create a new area load. Under the Geometry tab, select "Empty, on members only" for the Area of load application.

The area load can be displayed on individual members by right-clicking the load and selecting Display separately.

As of the version 6.03 (RFEM) and 2.03 (RWIND), the results calculated in RWIND can also be displayed in RFEM.

To do this, you just need to activate the "Wind Simulation" add-on in RWIND and start the corresponding calculation.
RWIND appears and performs the simulation. Once the calculation has been completed, the following dialog box appears.

By clicking "Yes", RWIND is closed and RFEM loads the result data. In the result display in RFEM, you can now display the properties related to the surface, as shown in the following image. You can use the navigator in the top left to switch between the results of the structural analysis and the wind simulation.

Corrugated web beams allow for further optimization of steel structures. They are often used to reduce the self-weight of main load-bearing elements and to prevent buckling failure of webs due to the corrugation.

This example will be based on a WTA – 1250 – 300x20 Beam from the Zeman catalogue.

To create a model of this beam, it's best to start by modeling a sine wave that will be used to edit the web. This consists of the steps shown below and in the attached images.

• Create nodes representing sine function
• Copy nodes to desired length of beam
• In RFEM's Lines table, manually create spline from 1st to last node

After these steps, it's recommended to create a parametric section with the dimensions of the corrugated beam. Members using this section can later be transformed into surfaces.

• Create a parametric section with the geometry based on desired beam
• Generate surfaces from members

With this set of surfaces, it is recommended to copy the sine spline into the position of the top and bottom edge of the surface representing the web.
Later, it is required to change the geometry type of the web surface to Quadrangle and redefine the boundary lines of this element.

• Copy sine into top and bottom of web
• Change web geometry type to Quadrangle
• Exclude straight lines from web surface and add sine lines

After preparing the geometry, it's required to focus on finishing the model for the calculation. Select the start and end lines of the member and create a member with the type Rigid. After that, it's possible to define nodal supports on the beam and loads in the model. In order to check the resulting internal forces of a member, it is recommended to define a result beam on the main center line. Finishing all of these steps allows us to start the analysis of the beam.

• Define rigid members on external lines of surfaces
• Add nodal supports
• Add loads – use line loads, not member loads for continuous loading
• Define a result beam on the center line
• Perform the analysis

Remember to define proper mesh settings with an adequate target length of the finite elements and to use a line mesh refinement on the sine lines.

The display of internal forces for couplings (coupling members, rigid members) is deactivated by default in RFEM 6 / RSTAB 9. However, you can quickly enable the display of internal forces and deformations for these member types under the Navigator - Results - Members options by selecting the "Results on Couplings" checkbox.