How to Calculate the Accurate Paint Area?

[chen_jiaye]

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.

[jeremy_tammik]

Thank you for raising the question here after our conversation on StackOverflow:

https://stackoverflow.com/questions/71455765/how-to-calculate-the-accurate-paint-area-in-revit-or-re...

I hope some of your peers can help you better than I can.

Are the original horizontal beams properly joined with the painted beam? Is the paint applied before or after they have been joined?

In any case, I also asked the development team whether they have any advice for you.

[chen_jiaye]

Thanks for your enthusiastic help!

Q: Are the original horizontal beams properly joined with the painted beam?

A: I think yes, but I don't know how to confirm? If necessary, I can upload my modeling files for everyone to check together.

Q: Is the paint applied before or after they have been joined?

A: The paint is of course applied after the connection. Because the first thing I have to do is to model and then fill in the areas that need to be painted on the model.

[chen_jiaye]

After thinking about it, I think this problem can also be simply and abstractly expressed as:

how to calculate the internal surface area of a building, and the surface area does not include doors, windows, floors and other parts that do not need painting.

[RPTHOMAS108]

Element.GetMaterialArea(ElementId, Boolean)

Where

ElementId is the Id of the Material you want to get the area of for the given element.

Boolean indicates if the material came from a painted material

You don't need to use paint you can use material of surface finish of the element and layers (for compound structure). This would work it out similar to the material schedule above.

Manually when you look at the geometry the visible graphical faces are the ones given a specific GraphicsStyleId, many of the hidden ones don't have a graphics style applied. 

The reliability of the results you get always depends on standard of modelling in Revit i.e. you'll get an additional area where two beams abut but don't join.

Considering a T-Junction of two beams with same depth I noticed  that the face that accepts the incoming beam has the same area as the face on the opposite side that doesn't i.e. the face area does not seem to account for the deduction of incoming beam (even though they have differing arrangements of edge loops). If you look at the edge loops of the face with the adjoining beam it has eight edges whilst the side without has four. Triangulation of the face that accepts the beam has six triangles. Whilst the opposite face has two triangles so can only represent one rectangular region. 

Since there is just one loop for each side I'm thinking the eight edges on the side with the incoming beam includes two short non-visible edges at the top and bottom (where the beam joins). If you look at the visibility of the edges two of them are indeed 'Contextual'. The length of such edges also matches the width of the incoming beam.

T-Junction