How do you select a static mesh material element by clicking the left mouse button in the running mode? I want to click on the model to get the material element of clicks to change the texture.

How do you select a static mesh element by clicking the left mouse button in the running mode?

Anonymous_0cb7be7ba4bc64b9dcbb8d10d6e603f5 (Anonymous_0cb7be7ba4bc64b9dcbb8d10d6e603f5) January 23, 2018, 10:57am 19

First of all,face index always print -1