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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 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. In these cases, 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. In this case, select not each individual face, but simply assign the whole solid part instead.

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 features for making a quick and easy selection via the viewer:

1. Box Selection

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.

2. 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.

3. Select Other

A handy tool for selecting a face hidden behind another face is the “Select other” feature. 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 9: Use “Select other” to select a face hidden behind another face.

4. 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.

In order 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 will be able to access the created sets in the right-hand side panel.
chow to create a topology entity set within the simscale simulation platform
Figure 8: Creating a topological entity set for the walls of a wing.

With these simple functions, users can save time during the set-up 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: June 25th, 2020

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