Why is it said that On Painting laid the foundation for the formation of the tradition of "Transfiguration" in Chinese painting?

Gu Kaizhi's theories in his On Painting, influenced by the style of figure appreciation and the metaphysics of the Wei and Jin dynasties, emphasized the transmission of the spirit, i.e., the portrayal of the spirit and character of the figure. In the expression of figure painting, the reproduction of a certain "form" is not neglected, but more importance is attached to the embodiment of "God". In order to paint the character's demeanor, the author emphasizes the depiction of the eyes and the interrelationships between the characters. The author also put forward the idea of "moving the mind and getting it right" in terms of artistic imagination, which had a great influence on later generations. On the basis of summarizing the creation of paintings by his predecessors, Gu Kaizhi elevated his own creative practice into theoretical understanding and used it to comment on the works of painters of his time, creating a precedent for theoretical criticism of Chinese painting. On Painting" laid the foundation for the formation of the tradition of "Transparency" in Chinese painting.