Generate Multi-Sphere Particles from a CAD Template

You can use imported CAD meshes created in other applications as particle templates that provide instructions on how to create a particle whose properties are automatically calculated.

To use a particle template:

Go to Tools > Options > Particle Display.
Click Import and navigate to the file of your choice.
Any templates used in your model must first be imported here.

Note: It is recommended to use a template if your model uses Multi-Sphere particles.
Select View > Templates to display the imported template.
You can also choose from the Templates option when a particle shape is selected.
Create spheres to match the template outline.

CAUTION: Data related to the particle template is stored in the *.ptf file. If you delete this file, the template information will no longer be stored within the model.

Generate Particles from a Template

You can create complex particle shapes based on a CAD template.

To use the Sphere Fitting tool:

Import a template from the Options menu (from the Particle Template) or click Edit to view the Particle Display menu.

The Generate Particle from Template dialog box uses an imported mesh template of the particle and adds spheres to fill the volume generating a Multi-Sphere particle.
Click Import and navigate to the file of your choice.
Any templates used in your model must first be imported here.

Generate a Grid

You can generate a grid around the imported template.

To generate a grid:

Enter the number of grid cells, in the X, Y and Z direction.

Increasing the number of grid cells will enhance the Multi-Sphere particle's fidelity, but will also increase its computational cost.

Smooth Values

After all spheres are generated, you must perform optimization to remove unnecessary spheres.

To smooth values:

In the Generate Particle from Template dialog box, specify a Smoothing Value.

When the Smoothing Value is greater than 1, the fidelity of the particle will be reduced and the total number of spheres will decrease.

The following Sphere table provides information about the smoothing factor and the respective number of spheres and smallest sphere size.

Table 1. Sphere Table
Smoothing Factor	Number of Spheres	Smallest Sphere(mm)
1	835	56
2	263	75
5	69	131
10	22	224

Set the Minimum Particle Size

You set the minimum particle size to ensure that there are no particles in the Multi-Sphere which are excessively small.

To set the minimum particle size:

See the Sphere Table to visualize the radii of spheres in the particle and manually determine a suitable value to use as a minimum radius.

Note:

Smaller spheres will require simulations to be run at a smaller Time Step, and will, therefore, be more computationally expensive. It is recommended that this setting is only adjusted after a few generation attempts as other options such as the hard boundary option may drastically affect the radius of the spheres.

Use the Hard Template Boundary

You use the hard template boundary option to scale particles towards the center of the template.

To use the hard template boundary:

Select the Hard template boundary checkbox to scale the particle down towards the center of the template to ensure that the created particle is of a similar size to the template. This option should be selected

Note:

You must use this option when using a large smoothing value. The smoothing value will grow particles outside the template boundary. The smoothing value increases the size of the spheres used to populate the particle, and can lead to a particle that is much larger than the template it was created from.
Do not use this option in instances where the center of the shape’s bounding box is outside the template, such as toroid, as the particles will scale towards that point.