PreonLab 5.0
Water Wading

August 12, 2021
Saba Golshaahi Sumesaraayi, Max Flamm and Andreas Henne
With the release of version 5.0, PreonLab saw several additions to it, ranging from new features to under-the-hood developments. They play an important role for wading simulations, which can be broadly classified as follows:

Performance & Accuracy:

  • Adaptive simulations with up to 3 particle levels
  • Faster Pressure Solver


  • Object Grouping
  • Improvements in the Plot Dialog
  • Improvements in the Connection Editor
  • Connect sensor right-click action

Adaptive simulations with up to 3 particle levels

In PreonLab 5.0, it is now possible to make use of 3 particle levels for the fluid phase. This brings PreonLab to the next level when it comes to optimizing simulations with large numbers of particles. Adaptive particle refinement allows to resolve specific regions with fine particles so that the flow physics can be captured with sufficient accuracy while the rest of the domain requiring less accuracy can be resolved with coarser particles. In vehicle water wading simulations, this is often the case since in most scenarios, the engineer is interested only in some specific regions enclosing the engine compartment or some specific part(s) of the vehicle. Moreover, in such regions, the gaps between the parts might be relatively small necessitating the fluid to be resolved with sufficiently fine particles. An example of using adaptive particle refinement with 3 particle levels is demonstrated below in a vehicle water wading scenario and is compared to the same simulation but using uniformly sized fine fluid particles. As can be seen, results of the two simulations are in a very good match not only visually, but also quantitatively. (Note that particles left to vehicle are clipped in order to make the comparison possible.)

Nr. of fluid particles: 185 million                        Nr. of fluid particles: 39 million

Fluid particle resolution: 5 mm                          Fluid particle resolution: 5/10/20 mm

Total simulation time: 70h (on 216 cores)        Total simulation time: 26h (on 216 cores)

A comparison of the front (blue) and rear (red) spring deflections between the cases with uniformly sized fluid particles and with refinement (3 particle sizes).

Improvements in the Pressure Solver

PreonLab 5.0 introduces an optimized pressure solver that converges faster and requires up to 30% less iterations. This improves performance in all cases that perform many pressure solver iterations, which typically happens in applications involving deep water. Depending on the depth of the water, this can accelerate vehicle water wading further.

Object Grouping

In real life vehicle water wading scenarios, hundreds of CAD files would be present in the simulation. Moreover, in most cases and based on the specifications of the problem at hand together with the needs of the engineers, tens of various boundary domains/conditions as well as cameras and post-processing sensors could be used in a single simulation setup. (For more details, read our article on post-processing for vehicle water wading in PreonLab here.) With the help of the Object Grouping feature introduced in PreonLab 5.0, it is now possible to have a better overview and control over the objects as demonstrated in the video below. Moreover, it drastically improves the usability and the performance of the Connection Editor, as will be discussed later.

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Video 1: Grouping solid parts in PreonLab

Improvements in the Plot Dialog

In PreonLab, all statistics can be plotted using the Plot Dialog. In addition to the possibility of exporting plot data as CSV files, plots can be exported as images. Now in PreonLab 5.0, it is also possible to seamlessly copy an image out of the Plot Dialog into the clipboard to be directly used in any document or presentation. Moreover, in PreonLab 5.0, having added the search functionality together with grouping the statistics by their corresponding objects and a complete renaming of statistics makes it now much easier to work with the Plot Dialog in vehicle water wading projects which often include tens of sensors and hundreds of statistics to be worked with. The video below demonstrates the ease of working with Plot Dialog for a real-life example of vehicle water wading simulation.

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Video 2: Improvements in the plot dialog; statistics grouping, search functionality and plot export

Improvements in the Connection Editor

In PreonLab, a connection establishes a relation between two objects. The user has control over the connections between all objects existing in a scene through the Connection Editor. When it comes to working with a huge number of objects in the Connection Editor, which is often the case in vehicle water wading simulations, it has now become not only much faster but also much easier. The newly introduced Object Grouping is very well realized in the Connection Editor resulting in a major impact on usability as well as performance. Furthermore, filtering connection types has also become more intuitive, which enables the user to focus more easily on the objects of interest and their connections when working with the Connection Editor. The video below shows an example workflow in Connection Editor for an actual vehicle water wading project.

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Video 3: Improvements in the connection editor

Connect sensor right-click action

One further step in improving the usability in PreonLab 5.0, is the introduction of the Connect sensor right-click action. With the help of this feature, the user can simply choose the solid of interest in the GUI and connect sensors to it in a fraction of a minute as shown below. All connections previously needed to be manually set in the connection editor with this regard are taken care of automatically.

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Video 4: Connecting sensors to solid parts via a right-click action and grouping them



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