Customizing Nuke with Gizmos - Nuke 101: Professional Compositing and Visual Effects - page 499

On the right, the two top buttons are Add and Pick. Both are ways to create new
knobs. The first lets you choose from a list of available knob types, such as a
slider,aSizeKnob,aTextInputKnob,andsoforth.Thesecondoneletsyoupick
from existing properties (discussed later in the chapter).
You want to be able to change the percentage in both X and Y. You can use a
Width/Height Knob that by default appears as one slider, but can be split into two
separate fields.
3. Choose Width/Height Knob from the Add button/menu ( FIGURE 12.10 ).
Figure 12.10. The Width/Height Knob panel opens so you can define the
knob's properties.