Multi-component mode lets you select faces, vertices, and edges without changing between selection modes. In this mode, you select components based on the cursor’s proximity to them.
To turn on multi-component selection mode for selecting one object at a time, do one of the following:
When you perform a marquee select on an object in multi-component selection mode and no components are initially selected, Maya will select all vertices in the marquee.
If a component or multiple components of the same type are already selected, then Maya selects components of the same type within the marquee.
If multiple components of different types are already selected, then Maya selects components based on this priority:
For example, if an edge and a face are already selected and you perform a marquee select on the object, Maya selects all edges in the marquee.