How to create Revit custom fill pattern
To make our drawings to look the way we want, we use fill patterns. For material surface patterns or filled regions we need to have the fill patterns loaded in our models.
If the desired fill pattern is not there, we can create custom fill pattern based on the standard rules available inside Revit environment. You can check HERE how to do that.
Of course sometimes the rules avaialbe inside Revit are not enough to achieve some sort of complex pattern. If this is the case you need to dig deeper. You will need to create custom *PAT file wich can be later imported inside Revit in order to control Revit fill pattern. About *PAT file logic and creation you could visit THIS page.
If you check the info page about creating *PAT files, you will see that this task is not easy and simple. To save time and efford, we use pyRevit add-in for Revit. You can download the add-in from HERE. It is free but feel free to support pyRevit project HERE. You need to draw only the repeating pattern with detail lines. Then with two clicks you need to define the boundaries and you are done. The result is fill pattern loaded in your model. You could also create automatically fill pattern or export *PAT file.