Fill out the form to download

Required field
Required field
Not a valid email address
Required field
Required field
  • Set up your own cloud-native simulation in minutes.

  • Documentation

    Selection via the Viewer (Tips & Tricks)

    A variety of quick selection tools are available within SimScale. This article aims to provide a brief overview of the various selection tools and their functionalities.

    Selection Basics

    In order to choose the right selection tools, here are a few basics every SimScale user should know:

    Choose the Selection Mode

    Centered at the top of the viewer, the viewer toolbar allows you to pick a selection mode. Usually, you either want to select whole solids or only specific faces.

    selection modes available in the workbench
    Figure 1: Choose the selection mode from the viewer toolbar on top of the viewer. Selection modes available (left to right): Solid, Face, Edge, Node.

    Depending on the context, either faces or whole solids need to be selected or assigned. In most cases only one assignment mode is possible. If this is the case, the workbench will automatically select the correct selection/assignment mode for you. In case a mix of assignments is possible, it’s common that you’d like to assign all faces of a specific solid part. If this is the case, select not each individual face, but simply assign the whole solid part instead.


    Mesh upload is mandatory if Edge selection or Node selection needs to be used.

    Selection Modes

    You might have noticed that a selection is sometimes shown in red, other times in blue, or even pink. The color used for highlighting a selection in the viewer depends on the current selection or assignment context:

    • Standard selection mode: red
    • Assignment mode (or contact master assignment): blue
    • Contact slave assignment mode: pink
    selection modes in simscales workbench
    Figure 2: Left: Standard selection mode. Center: Primary assignment mode (also used for contact master assignments). Right: Secondary assignment mode, used for contact slave assignments.

    Now that we have the basics covered, find below an introduction of the main selection tools for making a quick and easy selection via the viewer:

    1. Mouse and Keyboard Controls

    Besides selection tools, several functions are available via mouse and keyboard hotkeys. The table below shows an overview:

    EffectCommand (Windows)Command (Mac)
    SelectSimple left-clickSimple left-click
    RotateDrag with the left mouse button Drag with the left mouse button
    PanCtrl + left-click
    Drag with the middle mouse button
    Control + left-click
    Drag with the middle mouse button
    Open drop-down menu with options Simple right mouse click Simple right mouse click
    Zoom in/outAlt + left-click
    Drag with the right mouse button
    Scroll wheel up/down
    Option + left-click
    Drag with the right mouse button
    Scroll wheel up/down
    Box selection tool shortcutbb
    Hide selectionhh
    Save/confirm changesEnterEnter
    Escape/discard changesEscEsc
    Revert camera position and zoom level to default values aa
    Table 1: Mouse and keyboard hotkeys/shortcuts in SimScale

    2. Box Selection Tool

    This tool is commonly used in CAD software and also made its way into SimScale.

    Once “Box selection” is activated in the viewer, the user has two options to select the entities:

    visualization of the box selection available within the platform's selections tools
    Figure 3: Box selection activation icon and the two selection modes: fully contained (left) and intersection (right).
    • Clicking and dragging the cursor from left to right: entities fully contained within the box are selected;
    • Clicking and dragging the cursor from right to left: entities that are intersected by the box are selected.

    This type of selection comes in handy for geometries with a big number of faces. As an example, let’s have a look at the data center geometry below.

    data center geometry set up on simscale
    Figure 4: Server racks in a data center.

    It’s possible to quickly select all faces from a server line in one click:

    1. Make sure that the Face selection and the box selection icons are enabled;
    2. Create a box containing the entire server line. Note that, in this picture, the box was drawn from left to right.
    box selection within simscale
    Figure 5: Using a box selection in “fully contained” mode to select an entire line of servers.

    As a result, we select a total of 473 faces.

    using quick selection tools on simscale to set up a data center simulation
    Figure 6: Line of servers selected using the box selection tool.

    3. Invert Selection Tool

    In some cases, we would like to select the vast majority of faces in a model. Instead of selecting all of them one by one, we can simply select the ones we don’t want and then invert the selection.

    Let’s take the following example: we are interested in selecting all walls from a pipe geometry.

    The first step is to select the unwanted faces. In this case, 2 inlets and 1 outlet. Afterward, simply right-click in the viewer. In the window that opens, select Invert selection:

    viewer context menu containing the 'invert selection' option
    Figure 7: Invert selection tool: as a result, all pipe walls are selected.

    4. Select Other

    A handy tool for selecting a face hidden behind another face is the “Select other” feature. Now, simply right-click on a specific face in the viewer and when clicking on “Select other” a list of faces behind the current location will be offered for selection.

    how to use selection tools to select a face behind another face when setting up your simulation
    Figure 8: Use “Select other” to select a face hidden behind another face.

    5. Expand Selection

    SimScale offers options to extend the selection of faces based on the current selection, both in the Workbench and CAD mode environments. Users can extend their selection based on tangent faces, faces with the same area, and fillets with the same radius – these options are explored below.

    Tangent Faces

    The image below shows the steps to expand the selection based on Tangent faces:

    tangent selection in simscale
    Figure 9: Steps to access the tangent selection feature
    1. Select at least one face of interest
    2. Now, right-click on the viewer and choose ‘Expand selection’ from the list
    3. Select ‘Tangent faces’

    At this point, the platform selects all faces tangent to the initial selection.

    tangent faces selection in simscale
    Figure 10: This Tangent faces operation selects three faces

    Same Area

    Another possibility is to expand the current selection to other faces with the same area.

    same area selection simscale
    Figure 11: More than one face at the same time can be used as a starting point for the Expand selection tool

    As a result, all faces with the same area of the initial selection are added to the selection.

    expand selection same area result
    Figure 12: Result of the expand selection assignment

    Same Fillet Radius

    Oftentimes CAD models contain several small fillets which add little accuracy to the solution, but make meshing less optimized. The Same fillet radius selection is helpful in such cases, especially in the CAD mode environment when combined with the delete face command.

    In the heat sink model below, the CAD model contains dozens of small fillets. By selecting one of them, we can select all fillets with the same radius:

    same fillet radius selection simscale
    Figure 13: The Same fillet radius selection is especially useful for CAD clean up workflows

    As a result, all fillets with the same radius are added to the selection.

    same fillet radius selection example
    Figure 14: Result of a Same fillet radius selection

    6. Topological Entity Sets

    Topological entity sets are groups of faces that the user wants quick access to. It’s useful to create sets for groups of faces that will be used multiple times in the setup.

    To create a topological entity set, please follow these steps:

    1. Select the faces that will be part of the topological entity set;
    2. In the right-hand side panel, click on the ‘+’ button next to Topological Entity Sets;
    3. Give the topological entity set an appropriate name;
    4. You can access the created sets in the right-hand side panel.
    how to create a topology entity set within the simscale simulation platform
    Figure 15: Creating a topological entity set for the walls of a wing.

    7. Copy or Duplicate

    You can use copy/duplicate features to create the clone of a project, a simulation setup, a geometry primitive, a material, a boundary condition, or a result control item. It is usually practical to create an identical clone and edit it, instead of setting it from scratch.

    You can copy an existing project by pressing the copy icon as in the image below. This can be done also from inside the Workbench, look for the copy icon in Figure 1.

    how to copy a simulation project within the simscale simulation platform
    Figure 16: Copying a simulation project is possible in Dashboard as well as in Workbench.

    You can duplicate an existing simulation setup as well. This is practical if you would like to test the existing simulation setup with some minor changes; or if you would like to use the same setup on a new CAD model. The .gif below shows how to duplicate the setup and change the CAD model:

    Figure 17: Duplicating the simulation settings and changing the CAD model

    You can duplicate an existing setting by clicking on the menu icon next to it. This is possible for the following items in the simulation tree:

    • Geometry primitives
    • Materials
    • Subdomains under the initial conditions
    • Boundary conditions
    • Advanced concepts
    • Result control items
    duplicate material property data within the simscale simulation platform
    Figure 18: Duplicating a material

    You can duplicate the mesh settings on an existing CAD model. Alternatively, you can copy the mesh settings from another CAD model, as shown below:

    How to duplicate a mesh of the existing cad model or copy the mesh settings from anther cad model in simscale platform
    Figure 19: Duplicating an existing mesh or copying the mesh settings from another CAD model

    8. Fit To Screen

    In the right bottom corner of the Workbench or the post-processing environment, users can find the orientation cube that is helpful in adjusting the view angle. Additionally, the “home” icon is useful when trying to fit the existing model to the screen. Clicking the icon will adjust and zoom-fit the model appropriately within the screen.

    fit to screen home icon
    Figure 20: Fit to screen home icon highlighted. Left: Workbench, Right: SimScale’s online Post-processor.

    With these simple selection tools, users can save time during the setup of their simulations.


    If none of the above suggestions solved your problem, then please post the issue on our forum or contact us.

    9. Measurement Tool

    The measurement tool comes in handy when checking different dimensions of the CAD models. It can be useful to double-check the scale of your CAD with a specific reference, access dimension values easily, measure the distance between two entities, like edges or faces, and much more.

    You can find this option in the toolbar at the top of the viewer in Workbench or CAD mode.

    Using the measurement tool
    Figure 21: Measurement tool

    With this feature, you can work with two different approaches:

    1. Get the dimension value of a specific entity (volume, area, length, center of mass, etc.)
    2. Measure the distance between two entities

    Dimension Value of a Specific Entity

    If the goal is to know a specific dimension of an entity, select the entity (volume, face, or edge) and click on the ‘Measurement tool’ icon, The platform will open a new window with the dimension values.

    Selecting a face to calculate the area
    Figure 22: Measuring a face area

    It is possible to obtain the radius or center points of a region by selecting its edge.

    Selecting an edge to calculate the radius and center point
    Figure 23: Measuring an edge dimension

    Measuring the Distance Between Two Entities

    Using the measurement tool you can also check the distance between two entities. To work with this option, instead of selecting one entity you must select two entities and the tool will calculate the shortest, longest, and normal distance between the entities and the angle.

    Calculating the distance between two edges
    Figure 24: Measuring the distance between two entities

    To visually identify how the distances between the selected entities were calculated, simply place the mouse over one of the calculated values in the panel and you will see a line connecting the points:

    Checking the longest distance between two different regions
    Figure 25: Longest distance between the faces

    Last updated: September 18th, 2023