To calculate projection area in ParaView, we need to use calculator to do projection first. An example can be found in Fig. 2. After that use IntegrateVariables filter to calculate the projection area, as shown in Fig. 1, but you need to devide the number by 2.

Figure 1: To calculate the projection area, choose cell data.

Figure 1: To calculate the projection area, choose cell data.

Figure 2: Setting in ParaView. In this case, flow is along the x-axis and we need to project the fist into yoz plane.

Figure 2: Setting in ParaView. In this case, flow is along the x-axis and we need to project the fist into yoz plane.

Here is a testing case using a ball with diameter of 20 mm. Using the same steps mentioned above, the area is calculated as 2511.84 mm^2. However, the true area is \(A = \pi * r^2\), 1256 mm^2. You need to devided the measure in Paraview by 2, so \(A = 1256\) mm^2.

Figure 3: The area considers both side of the projected area.

Figure 3: The area considers both side of the projected area.

Figure 4: To calculate the projection area, you can use calculate filter.

Figure 4: To calculate the projection area, you can use calculate filter.

The projected area is 0.0076095 m^2.