Do you know, that… ?

Having imported the file, which contains surfaces, you may have trouble creating a drawing.

By default, the program does not show the surface, therefore there is a void in the drawings in these places.

How to solve it?

You need to make a cut… but like this, that intersects nothing.

Simply, the cutting line must be in front of the element, then the section is a projection. But be careful, you need to enable the option Display surface features to show the surfaces!