I am a newcomer who has just used the ultimaker cura 3.0. Recently my research project required me to print some propeller models. There are my shaft holes and keyholes in my propeller model. These can be seen in the picture. But when using the software, I found that the shaft hole in the propeller could not be printed. It is filled. Can anyone help me solve this problem or make some suggestions? Is it a problem with my parameter settings? My model is imported using the STL. file.