Unity basics - terrain production
https://www.jianshu.com/p/7d5fa8f5169a
Unity terrain splatalpha research terrain map export replacement and drawing
https://blog.csdn.net/shenmifangke/article/details/52638716
Unity Terrain Basics
https://www.jianshu.com/p/cbabccdcc459
Unity3D game development terrain system (4)
http://gad.qq.com/article/detail/22380
Unity engine rendering technology learning minimalist roadmap
https://zhuanlan.zhihu.com/p/33432743