Reflections
Learning how reflections work is simply a matter of studying the real world. As I mentioned in Chapter 1, I never guess at what something should look like, I study models and real-world objects to determine how something should work.
Let's say you wanted to create an image of the straight-on view of an object being reflected into a mirror. You would only need to take the object and flip it horizontally (Edit > Transform > Flip Horizontal) to get a fairly decent reflection. If, however, the mirror was placed below or at an angle to the object, flipping the object vertically or rotating it would not be enough to produce a proper reflection. In this case, the reflection would show the bottom or unseen sides of the object, requiring you to alter the shape to produce the final effect.
In the following example, note the reflections of the neon tubes on the orange, plastic letterforms of the sign (Figure 4.3). Creating the reflections was an easy task but making them look right required a little alteration.

Figure 4.3 The neon tubes can be seen reflected in the orange, plastic surface of the sign.
The tubes were created exactly as the neon tubes in the previous chapter. The difference here is that the tubes are attached to a plastic surface that is reflective.
To create the actual reflection, I simply duplicated the layer that contained the tubes. Next, the layer was offset to the lower right to match the viewing angle (Figure 4.4). I renamed the layer "Paul's tubes refl" to differentiate it as the reflection layer. It was then turned into a clipping group with the layer that contained the orange letterforms (Figure 4.5).

Figure 4.4 The layer containing the neon tubes was duplicated and offset to the lower right.

Figure 4.5 The duplicate layer was clipped with the layer of the orange plastic.
The one thing that needed to be altered was the area where the tubes bend inward toward the sign to connect to it (Figure 4.6). These tubes are bending away from the viewer toward the sign. But in the reflection they should appear to be bending the opposite way toward the viewer and away from the plastic sign. To accomplish this effect, I replaced the end of the tube with a new shape that would resemble a proper reflection, as shown in Figure 4.7. I also recolored the tubes to better simulate the soft reflection.

Figure 4.6 The end tips of the neon in the duplicate layer needed to be altered to act like a true reflection.

Figure 4.7 The tips in the duplicate layer were altered and recolored to look like a reflection.