I am not sure if Revit is part of the Stackoverflow community but it seems that the Tag already existed so I decided to give it a try.
I have created a section of my 3D model. In order to export it as a PDF, I have created a new sheet and I have dragged a 2D of a section onto the sheet.
On top of the 2D section I needed to add some elements as filled areas with different hatches. When I check the areas on Revit, they are shown with a non transparent background (the section's lines of a 2D drawing are not visible behind), nevertheless when exporting it to a PDF the areas are transparent and I can see the section lines through them.
When checking the settings configurations for transparency filled areas the value is set to 0. Therefore, I would have expected not to have any difference between the Revit view and the PDF version (meaning non transparent background)
Am I missing something?
The StackOverflow tag is actually revit-api, standing for the Revit API, the built-in .NET programming interface. The API wraps the UI for automation purposes. Do you know how to achieve what you need manually through the end user interface? If so, that knowledge will be very helpful to determine how to achieve the same programmatically. If not, it can probably not be achieved programmatically either. The best place to raise a question to determine how to achieve the desired result manually in the user interface is the generic Revit Architecture discussion forum.