Selection Functions: Select by 2D Region

Description

The Select by 2D Region function performs selection operations on entities based on the current view angle. Entities are selected based on their position in screen space, unlike Selection Functions: Select by 3D Region, which selects entities in model space.

The function offers four modes of operation.

Single-click

In this mode, a left-click-and-release action is performed on a single visible entity in the model window to select it.

Selection operations can be performed on multiple entities by clicking-and-releasing each one in turn.

The click point does not need to be exactly on an entity; the function searches for the nearest entity within a certain number of pixels (see View Settings: Selecting Tab).
Left-click-drag

In this mode, a single rectangular selection box is drawn on the screen by holding the left mouse button and dragging.

When the mouse is released, the selection operation is performed on visible entities that are partially or wholly enclosed by the selection box.

This mode cannot be used to select entities that are fully obscured by other entities; if an entity is obscured, it is not selected.
Left-click-drag+Alt key

In this mode, the Alt key is held pressed while a selection line (not box) is drawn on the screen by holding the left mouse button and dragging. The line need not be parallel to the horizontal or vertical edges of the model window.

When the mouse is released, the selection operation is performed on visible entities that are intersected by the line.

This mode cannot be used to select entities that are fully obscured by other entities; if an entity is obscured, it is not selected.
Left-click-drag+Shift key

In this mode, the Shift key is held pressed while a double rectangular selection box is drawn on the screen by holding the left mouse button and dragging.

To distinguish this mode from the Left-click-drag mode, a slightly different selection box is drawn - this selection box uses two closely spaced parallel lines to draw the edges of the box, whereas the Left-click-drag mode uses one line for each edge of the box.

When the mouse is released, the selection operation is performed on all entities that are partially or wholly enclosed by the selection box, similarly to the Left-click-drag mode. Unlike the Left-click-drag mode, the selection operation for this mode is also performed on obscured entities, as long as they are partially or wholly enclosed by the selection box.