In the .ipt you do not have the ability to "section" the part. You can however create a sketch (on either a workplane or a feature plane of the part if the feature corresponds with the area you wish to cut) and then RMB and select Slice Graphics. This will remove everything that is between the camera and the sketch. If it doesn't remove the right material un-check Slice graphics, rotate your view 180° and redo the command.