Fill out the form to download

Required field
Required field
Not a valid email address
Required field
Required field


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:

Simple left-clickSelect
Drag with the left mouse button Rotate
Ctrl + left-click
Drag with the middle mouse button
Simple right mouse click Open drop-down menu with options
Alt + left-click
Drag with the right mouse button
Scroll wheel up/down
Zoom in/out
bBox selection tool shortcut
EnterSave/confirm changes
EscEscape/discard changes
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. Tangent Selection

Another option available in the Workbench is Tangent Selection. The image below shows the steps:

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. Choose to select the ‘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

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 11: 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 Figure 12. 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 12: 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:

how to duplicate a simulation setup and change the cad model of the setup within the simscale simulation platform
Figure 13: 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 14: 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 in Figure 15.

How to duplicate a mesh of the existing cad model or copy the mesh settings from anther cad model in simscale platform
Figure 15: 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 16: 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.

Last updated: November 26th, 2021