You can place 5 different light direction textures of a object, press G or click the button to create a normal map.
Idea from a video:
https://www.facebook.com/NormalMapCamera/videos/1594890717506146/
放五張不同光源方向的貼圖以建立一張normal map(法線貼圖)。可按G或點擊按鈕。
發想自一段影片：
https://www.facebook.com/NormalMapCamera/videos/1594890717506146/