SPARK3D User Manual
Specifying Regions

The high power analysis of a device can be carried out in two different ways:

There are different reasons to take advantage of user-defined regions. As long as the device is divided in several areas it is possible to compare the breakdown threshold of each one and determine where the discharge will take place. Besides, computing the breakdown onset on specific regions is faster than taking into account the whole circuit. Finally, the user can increase the mesh density involved in the solution of the problem improving the precision of the calculation and avoiding memory overflow limitations.

Prior to the creation of simulation regions it is advisable visualizing the electromagnetic fields in order to detect the critical areas of the structure in terms of breakdown.

Working with regions

A region of study corresponds to a box, which is defined through its center and size. These input variables can be determined from the visualization window of Paraview, where a cube axis helps us to obtain their values. In our example, the regions will be defined through the following values:

RectangularRegion 1 x y z
Center (m) 0 0 0.0245
Size (m) 0.024 0.01 0.006
RectangularRegion 2 x y z
Center (m) 0 0 0.017128
Size (m) 0.024 0.01 0.006
RectangularRegion 3 x y z
Center (m) 0 0 0.032038
Size (m) 0.024 0.01 0.006

In order to define an analysis region, you should double click on the Analysis Regions tree item of SPARK3D. A new window will be opened:

On the left hand side of the window, you see the tree corresponding to all existing regions. By default, there is a predefined region named Circuit, which takes into account the whole imported model and is enabled for analysis.

From this window you will be able to:

By clicking on a specific region you can modify its defining properties. Click on RectangularRegion 1 and you see that in our example the input variables:

Center x, Center y, Center z

Size x, Size y, Size z

have the values given in the table above corresponding to one of the analysis regions. Note that the units of these variables are ALWAYS meters.

The validity of all defined regions will be checked when accepting the actions done through the OK button. It checks if every region contains any mesh points. If there is some region which is not correct, an error message will pop up and you will have to adjust the region's properties so that the region intersects the device.

Besides, you can also visualize the relative position of all regions with respect the structure under study. Press Visualize button and you see that the defined regions correspond to the critical areas previously recognized in the lowpass filter.

Through the 3D CAD viewer it is possible to modify the defined boxes and visualize at once the changes. From the Pipeline Browser located on the left hand side of the window, select the box you want to modify (see the figure above, where RectangularRegion 3 is chosen). Then in the Object Inspector window select Properties tab, where the geometrical parameters of the box, that is, its dimensions and center position, will be displayed. You can change them and by clicking on Apply button you can see the result of the modification. It is important to point out that the changes made in the 3D CAD viewer will not be automatically transferred to the defining parameters of the regions. Once you have found the proper values that suit your problem, you have to write them in the corresponding cells of the Analysis regions window of SPARK3D.

If you want to create a new region you just click on Add region button. A new region will be created with a default name that you can change with the Rename right-click option. You can fill in the input parameters. On the contrary, if you want to erase a region, you should select it and either select the Delete right-click option or directly press the Supr button. You can also copy and paste one existing region through the corresponding options by right clicking on the selected region.

Once you have done all your modifications, you can either preserve them through OK button or discard them through the Cancel button (or alternatively closing the window).


When checking the validity of a region it may occur that it is not correct, that is, there are no mesh points inside it. The reason for this could be one of the following: