Here some useful references about Japanese traditional architecture, in particular about roofing. First, nowadays there are 3 standard tiled roof types in Japan:
J-shaped tiles: these are Japanese style tiles, the main tile is named 桟瓦 (sangawara); these tiles are the evolution of the traditional 本瓦葺 (hongawara roof) still used for temple and shrines; they are used for traditional houses;
F-shaped tiles: these are flat tiles;
S-shaped tiles: these are Western style tiles.
All data necessary to model all tiles for these 3 types of roof can be found on this website. I used it for to reproduce the sangawara roof, as I am mainly interested in traditional Japanese buildings. Here the result in UE5
The most interesting and complex Japanese roof type is, however, the hongawara one. For this type of roof, I have found a lot of interesting material on the web:
This page explains the main differences between the Japanese style roof and the Hon style roof used in temples, Shinto shrines and castles. They are both traditional Japanese roofs, so a lot people are confused about it and the author, who is a roofing expert, tries to clarify the difference;
This other page explains how the 2 main tiles for the hongawara roof (平瓦hiragawara and 丸瓦 marugawara) evolved in a sole simplified tile, the 桟瓦sangawara;
This video on Youtube is very useful and interesting to understand the whole process of building an hongawara roof;
Finally, some interesting information about traditional Japanese architecture can be found in the papers and books of Adriana Piccinini Higashino (Associate Professor at the Architecture Department of the National Institute of Technology, Akashi College, Japan).
Now, in order to relax after all this reading a nice video