The Nuke 3D Engine - Nuke 101: Professional Compositing and Visual Effects - page 387

Now that you have the axes, you can click them and move the camera around.
You can also use an individual axis to move in one direction. The reason the axes
are in three colors is to help you figure out which is which. The order of colors
is usually: red, green, blue. The order of directions is usually: X, Y, Z. In other
words, the red-colored axis controls the X direction, the green one controls the Y
direction, and the blue controls the Z. Very convenient and easy to remember.
The same happens with rotation.
4. In the Viewer, hold down Ctrl/Cmd and watch the axes change to show the rota-
tion controls ( FIGURE 9.6 ) .
Figure 9.6. Holding Ctrl/Cmd lets you control rotation.