If you draw a window from right to left, all parts that are even partially included are selected.
In addition to the default rectangular selection window, you can use a rhomboid, ellipse, or circular ring (point to "Select" on the "Edit" menu).
If you want to select part of the rendered model, there is a risk that you will inadvertently move an object by drag‑and‑drop instead of selecting it. To avoid this, press [Alt] during the selection.