Scale Model Animation 5 – Building Building Animation
Building Animated Characteristics—A Matter of Timing
What makes one think that there is life in a building (or structure if you want)? Movement is always the most obvious thing to me. But movement within a building may be too small for all but foreground buildings that can be closely scrutinized. There is, after all, limited visibility inside a building, particularly older buildings that likely have smaller windows. Movement at the window could include movement of the window itself, shades, shadows, silhouettes, or figures at or near the window. Roof vents, some large fans, and door movement would also apply.
But for any building near or far, lighting changes really can stand out. Lighting a building is easy enough… or is it?
The effect of a single light to illuminate an entire building renders it toy-like to me. The light usually appears to be a point source for multiple rooms, if not multiple floors. The illumination falls off in an unrealistic way. So, we can shift to multiple light sources -- lamps and/or LED (Light Emitting Diodes). Multiple lamps in an enclosed volume, especially a sealed volume, generate heat that can deform plastic and age wood and paint. Thus, for building illumination of all sorts, LEDs are the light source of choice. They also can generate more light per milliampere of current. LED color can be a problem, but white LEDs and liberal use of Tamiya Clear acrylic paint can yield most any color you might want.
But just lighting up windows isn’t good enough. Observation of real buildings shows light turn on and off over time as the day moves on. So turning lights on and off is the key—realistically, of course. When I first started switching lights for effects, it was with a rotating drum and a set of contacts for each light, something like a player piano roll. But the sequence was short and eminently predictable. Later, I learned to use a “shift register” which is an integrated circuit which simply shifts bits in one direction. A simple variation is next:
You can use the QA, QB,- -,QH outputs to drive the cathode (minus (--) side) of a LED in series with a resistor. The 74LS30N is used to insure that there is only one light on (“Qx” bit Low). By leaving some other LEDs always on, you can use this circuit to turn others on and off. The sequence, however, is entirely predictable, and that always bothers me. The next circuit below uses exclusive OR’s in the shifter return (feedback) path to “scramble” the sequence. It is still predictable but adds “disorder” to the sequence, disguising it somewhat. The circuit is incomplete, meant only for illustration.
If you use the following outputs (from the 74LS164 to the 74LS86 Exclusive OR) for feedback you will get sequences that will not repeat for 255 cycles:
[QH, QG, QF, QA]
[QH, QG, QE, QC]
[QH, QG, QC, QB]
[QH, QF, QE, QD]
[QH, QF, QE, QC]
[QH, QF, QE, QB]
Long sequences that do not repeat up to their maximum length are sometimes used as “pseudo-random number generators.” These are better for non-obvious lighting sequencers but, even if slowed down, they can generate sequences for building lights that look more like Christmas tree lights, than a scale model building animation. Why? Typically, people don’t really randomly turn lights on and off. Once we might enter a room and turn a light on, the light tends to stay on for a while—it has a distinctive “dwell time.” Shift registers like the ones above, and mechanical timers have difficulty simulating the equivalent effects. Generally, I enjoy the lights better if they stay on for about 70% of the time. They still cycle on and off, but they are mostly on. Lighting changes are also time-of-day-based. One would expect to see flurries of activity in early morning, at dusk, and perhaps 10 PM to midnight, depending on the nature and characteristics of the building.
Building Animated Characteristics—More Timing Issues
Now you might say that room lights simply turn on, and turn off some time later—well… yes, sort of! Incandescent room lights would follow this pattern, but there are other kinds of light in a room. Candlelight, for one, flickers quite slowly, if at all. So would the light from a fireplace. They are likely dimmer lights too, and lower to the floor. Fluorescent lights are typically overhead, and are usually quite bright. But older fluorescent lights come on with a quick flicker before they steady up; they also turn off instantly. Television sets can sometimes be the primary lighting in a room and also flicker over time, but in bursts, unlike a candle. Decorative lights and special function lighting might exhibit other effects. Mechanical devices, like the interference of a fan blade with a point source of light can create special effects. Figures placed between a light source and a window can create silhouettes. Working machinery and tools can create sparks, flashes, etc. within a building. The changes that all the effects achieve can add life to an otherwise static building.
Building Animated Characteristics—A Matter of Color
Change can also occur based in part or in whole by color. A television can obviously fill a room with an array of colors, and changing colors could indicate a TV’s presence. An old black and white TV usually cast a blue tint to a room, and would be appropriate for a late 1950’s-1960’s setting. Fluorescent lights very often have a blue tint, especially with industrial lighting. Gas lamps when turned down created a light with more red and orange, than a brighter white/yellow when fully turned on. Sparks from machinery could be yellow, blue, white, etc. and welders often generated a bright white light with flickers of blue. Like allot of other modeling details, it takes some practice looking for the details that we often just take for granted in the world around us. I constantly pick up more examples and more variations too. Here are some variations, simulating incandescent, fluorescent, and party ceiling lights.
Here’s the welder close-up and a real building example:
Building Animated Characteristics—Sound Concerns
Where there is life, one usually notices sound of some sort. When I look to build any animated scene, I always consider sound in two ways: background sound, and point sounds. Since I am explaining how I approach this, let me also explain that there are other points of view, and they may even achieve more, but this is how I do it. I think about background sounds as the sound of the unseen and indirectly seen. That is, if there is some action creating the sound, it is hidden in the scene. This would include sounds of the wind, rain, crickets, birds chirping, dogs barking, some machinery, voices, etc. I often think of these sounds as setting the mood or creating the ambiance of the scene. These sounds are typically not loud, and for modeling may be barely noticeable. In fact, many argue exactly that. I have noticed that I enjoy these sounds much more if they are generated with great fidelity- the better the quality of reproduction the better I enjoy it.
What I call point sounds are those which can be easily and clearly identified by an animated (read moving/changing) source. While I really crave higher quality sound for the background, I tolerate noticeably poorer sound for point sources. Why? I’m actually not sure, but it likely has to do with control, duration, and cost. Point sounds need to be cued in synch with movement and change. This can be done within programmable DCC decoders, like the Digitrax SDN144PS that I have used in other animations (like
and ). In the building animation, I am starting to experiment with a new (for me) sound module, the WTV020-SD-16P. A Google search will yield multiple sources, many in China. It comes in a version that is computer (Arduino) controlled, uses 1GB micro SD memory cards, and handles up to five hundred, 16-bit 32KHz sampled, mono sound files on a memory card, and play them back in any order.Many aspects of building life into buildings require the simple, but programmable control I use. Everything including a desktop, laptop, Arduino microcontroller, PIC microcontroller, and TI Launchpad microcontroller could be used. Use whatever is comfortable, available, and affordable. All can be made to work. A $6 Arduino Pro Mini together with a $5 WTV020-SD-16P is a good combination for me, and is quite small. You can see the early results below of a building I put together as a teaching aid for a clinic I’ll be giving on animation control at the National Narrow Gauge Convention in August in Pasadena. You could try to see if you can notice any repeating patterns… but you won’t be able to find them. The sequences don’t exactly repeat at the rate currently set, for something like 14 hours or so, and the video isn’t nearly that long! There are four sets of six audio tracks: two voices, one party track, and one background track. In theory, that would generate 6 X 6 X 6 X 6 (1296) combinations before repeating! Next time I’ll get more into the construction details. See if you can spot some of the Building’s features in the video, built specifically for animation. Remember, this is another “project in progress!” All the sounds you hear are generated by the animation, and not edited or dubbed for the video.
I hope you enjoy any surprises you may find along the way—remember model railroading is FUN! and so is scale model animation! More to come…
Have fun! 
Best regards,
Geoff Bunza
