Generating Particles for Complex Geometries Using WELSIM

With the development of modern engineering simulation, particle-based simulation has been increasingly adopted by the industrial community. Particle-related computations and software have emerged in various fields of engineering and science. In addition to pure particle simulations, such as molecular dynamics, there are also coupled methods with continuum approaches like the finite element method, enabling more sophisticated simulations. An example is the SPH (Smoothed Particle Hydrodynamics) method, which simulates the motion of fluids and granular materials. As a result, the demands on particle simulations are also rising. Particle generation is the first and most critical step in all such simulations. Therefore, algorithms and processes for generating particles are particularly important. The author has previously discussed numerical methods for generating particles in the article titled “Automatic Generation of Simulation Particles.” Press enter or click to view image in full size Generating particles for simple geometric models, such as cubes, is not difficult. However, when the geometry becomes more complex, particle generation becomes challenging. Currently, there are not many software solutions on the market that can generate particles for arbitrary shapes. WELSIM is already capable of handling this well and can export particles as external files for use in other software. This article provides a brief introduction on how to generate particles in WELSIM. 1. Open WELSIM and Import a STEP Geometry Model In this example, a cylindrical model with a circular hole is imported. Set the geometry’s Create Particles property to True. Press enter or click to view image in full size 2. Click the Meshing Button to Automatically Generate Particles In this setup, 441 particles are generated. Press enter or click to view image in full size 3. To Increase Particle Density Modify the Maximum Size value in the mesh settings. When set to 0.01, the particle density increases. 4. Adjust Particle Display Size for Clarity When the number of particles increases, it helps to reduce their display size for better visibility. In the 3D View of the mesh object, set the Particle Size value. Here, it is set to 0.001. Now, a larger number of particles can be seen — 16,060 in total. WELSIM thus allows for easy and efficient generation of particles at any desired density. Press enter or click to view image in full size 5. Export the Particles Once particle generation is complete, export the particle file. Right-click the Mesh objectand select Export Particles from the context menu. Press enter or click to view image in full size 6. In the Export Dialog Enter the filename and choose the export format. The current version supports the VTK PolyData format. More formats will be supported in future versions. Press enter or click to view image in full size The exported file can be loaded and used by other software. For example, ParaView can be used to visualize the exported particles, as shown in the image. Press enter or click to view image in full size Conclusion This article outlines the steps for generating particles using WELSIM. Users only need to import a geometry in STEP format and, through an automatic mesh-like method, can quickly generate particles at various densities. Although a simple geometry was used here, the same process can be applied to complex models. The software also supports exporting particle data for use in other applications. The particle generation feature is already available in version 2025R3 and will continue to be improved in future releases. WELSIM has no direct affiliation with the author or the developers of ParaView. ParaView is referenced here purely as a technical example for demonstration purposes.