When you work with NURBS models, you often work with sub-objects. While you are at the sub-object level, you use the usual selection techniques, such as clicking, dragging a region, or holding down Ctrl, to choose one or more sub-objects.
You can also select NURBS point, curve, and surface sub-objects by name. Turn on the Keyboard Shortcut Override Toggle, go to a NURBS sub-object level, and then press the H key. This displays a Select Objects dialog that lists only sub-objects at the current level. Choose one or more objects in the list, and then click Select. You can assign your own names to NURBS sub-objects (aside from CVs) that you want to edit frequently.
Press Ctrl+H to have the Select Sub-Objects dialog list only sub-objects directly beneath the mouse cursor.
The H shortcut is also a convenient way to choose parent objects while you're creating dependent sub-objects.
When you work with NURBS, you switch frequently between the object and sub-object levels, or from one sub-object level to another. Keyboard shortcuts and pop-up menus can help you do this.
The Sub-Object Selection Toggle (default: Ctrl+B) switches between object and sub-object levels.
The Cycle Sub-Object Level shortcut (default: Insert) switches from one sub-object level to another.
When you right-click in a viewport while a NURBS object is selected and the Modify panel is active, the quad menu lets you switch between various levels of the NURBS model: Top Level, Surface CV Level, Surface Level, Curve CV Level, Point Level, Curve Level, and Imports Level.
The command panel’s right-click popup menu (available whenever the mouse cursor becomes a pan hand) helps you navigate the rollouts on the current command panel.
If you have a three-button or wheel mouse, rolling the wheel scrolls the command panel.
Sub-object selection sets are persistent. If you go to a different sub-object level, when you return to the previous level, your selection is still available. However, refining or inserting points or CVs makes the sub-object selection sets invalid for that object.
You can move a sub-object selection set among sub-objects at the active level of the NURBS model by holding down Ctrl while you press the arrow keys.
When you select surface CV sub-objects that are "on top of" each other in a 3D view, sometimes all the selected CVs fail to highlight. To fix this, choose Customize > Viewport Configuration, and turn on Z-buffer Wireframe Objects.