**4.1. Multiple layer viewing**

We can display results in multiple 2D sections with variable transparency. This method of results visualization can give us much better overview of how a situation looks like.

It can be also beneficial to use surface view as semi-transparent layers to view results in semi-masked way. Through this we can highlight some regions of model without completely blocking visual output from other regions. For example, in our case, we can use one surface view of *RMS|E|* in agar phantom and semi-mask it with alphamap of tumour (values 1) and the rest of tissue (values 0.5).

Figure 19. shows us how this graph is plotted and how transparencyMatrix is prepared.

Note that when using this type of transparency mapping maximum and minimum values must be present in transparencyMatrix (i.e. one edge of transparencyMatrix is set to 0 to denote the minimum value of transparency).

**Figure 17.** Sliced View of *RMS|E|* [dB] (only in agar phantom, colormap hot, jet, alpha 0.7)

**Figure 18.** Surface View of RMS|E| in [dB] (transparency of tumour region set to 1 – opaque, transparency of other regions set to 0.5 – semi-transparent; colormap – jet and lines)

Through this method we can produce much more intricate visualizations of results which are unseen in commercial EM simulators. For example we can mask results in uninteresting regions (immediate vicinity of power source etc.) almost entirely, semi-mask results in exposed tissue and left results in tumour unmasked, vital organs and other key regions of simulation domain. Note that masking results with transparency matrix does not alter presented values.

This may pose a problem when values around a power source are extreme and render the rest of results unclear. For this purpose you may consider utilizing simmilar approach as presented in Figure 7. Instead of finding values lower than some value you may find values higher than some reasonable value and lower all higher values to this level.

Many more possibilities are offered thanks to post processing of EM results in Matlab. As mentioned before, the greatest advantage is that it is extremely flexible and can meet very specific requirements which can arrise with various applications of EM field. In the following section we shall demonstrate some results obtained during our primary research of EM field of microtubules (nanostructures in living cells which serve as a crude frame of a cell and have other important roles in life cycle of a cell).

Post Processing of Results of EM Field Simulators 37

**Figure 19.** Fig. 19. Generation of Overalaying Transparency Matrix and Its Utilization
