After finishing building the roof, we were supposed to combine the roof and the body of the building together. However, there are gaps between the roof and the body. Therefore, I looked for the references of traditional Chinese architectures, and I found out that most of them, there are wooden structures filling up the gap.
Therefore, I need to add another layer between the roof and the body.
Convert polygon edges to curves again and extrude them:
Use the Multi-Cut tool to add lines to the roof, then extrude them
Arrange the cubes I made
Final look