To view cross-sectional cuts of your model, you can enable up to six section planes.
An enabled plane affects (cuts through) the scene. The current plane is the one that is rendered visibly in the view. Selecting a plane as current automatically enables that plane.
When a section plane is first enabled, it is created with the default alignment and position. Afterwards, enabling a section plane restores the saved alignment, position, and rotation if they are available for the current viewpoint.
By default, a section plane is created within the view, and as close to the center of the view as possible. Visually, a section plane is represented by a light blue wireframe. You can hide the visual plane representation by toggling the corresponding gizmo button.
There are 6 fixed alignments: top, bottom, front, back, left, and right.