I am trying to convert an imported file (with surfaces) to a solid model. I have limited knowledge of any of the features that are supposed to resolve this issue. I have tried "Knit Surface", "Thicken", "Filled Surface",.. none of which are helping me with this issue.
The file shows all of the external features. However, I need to make a cutout in this model and when I attempt to do so, I do not get anywhere. I am unable to "Extrude-Cut". When I do a section of the part, I can see that it is hollow.