How to Calculate the Accurate Paint Area in Revit or Revit API?

Question

I have completed the 3D modeling of the building in Revit, and now I want to calculate the area that the building needs to be painted in order to estimate the project price.

However, I spent a lot of time trying many methods (Creating Parts, Split Faces, Paint), and I couldn't get the desired result in the end.

Next, I will describe the problem I encountered in detail:

① We can see the beam system of the building in the picture, use the "Paint" function to add yellow paint to one of the surfaces, and its area is (7.15m * 0.9m = 6.435㎡).

② Use "Isolate Element", we can see the yellow paint on this surface (including the part that intersects with other elements). In the material schedule, we can see that the area of the yellow paint is 6.44㎡.

③ In fact, since this beam intersects with other beams, it is impossible to paint the intersecting part when painting during construction. Therefore, the calculated 6.44㎡ is larger than the actual one.

④ In order to better illustrate the problem, I added two additional structural columns with the same volume as the intersection (which do not exist in reality).

⑤ At this time, use "Isolate Element", we can see that there are two gaps on the painted surface (both 0.2m * 0.7m), so the area of the remaining part is (7.15 * 0.9 - 0.2 * 0.7 * 2 = 6.155㎡). In the material schedule, we can also see that the area of the yellow paint is 6.16㎡. This area is the real paint area in the actual construction.

However, this method looks stupid and it also destroys the true appearance of the building model, so I would like to ask if there is a more sensible approach? I have programming ability, and if secondary development is required based on the Revit API, it is acceptable to me, as long as the problem can be solved.