Why did the Northern Wei Dynasty make bronze (gold) figures first after its establishment? How did this custom arise?

The so-called casting of gold is a popular method of divination among ethnic minorities since the Wei and Jin dynasties, about its origin is no longer available. Let's try to speculate, hand casting gold people to measure the fate is not the beginning of the Tuoba Department, the Book of Jin once recorded that Ran Min, the King of Mourning, had sent Chang Wei mission to Yan, Murong Jun asked him: "I heard that the Ran Min casting gold for their own image, bad and not, how to say that there is a heavenly destiny?" That is to say, as early as the Ran Wei era, the casting of images to ask for heaven has begun to circulate. The earliest record of casting images originated from Buddhism, legend has it that King Yuchan had set up a sacred image of Buddha, and in the Western Han Dynasty of China, Huo Zaiwei went out to Longxi to crush the Xiongnu had been awarded a golden man of the King of Huotu's sacrifice to the sky, according to which it is presumed that this tradition should be a combination of steppe civilization and Buddhism, which was prevalent in the Later Zhao of the Shi family, and inherited it for the Tuoba Department, and was fixed as a system of setting up a queen at the beginning of the foundation period of the country.