Tutorial: Page (1) of 1 - 04/24/03 Email this story to a friend. email article Print this page (Article printing at MyDmn.com).print page facebook

Animating The Inanimate, Part One

3D character animation doesn't have to be all that difficult By Kevin Schmitt
"Three-dimensional character animation." A phrase that not only rolls right off the tongue, but, more importantly, conjures images of fantastical photorealistic beasts thundering their way across a silver screen near you. The flip side is that the same phrase, for many creative professionals, introduces a sometimes convoluted world of concepts like inverse kinematics, weight mapping, phenomes, NURBS, and so on. But fret not. Using tools present in most major 3D animation software and some simple objects and techniques, you too can begin to incorporate 3D character animation into your projects.

A couple of notes before we begin. First, I'm going to be using Newtek LightWave 3D 7.5b for these tutorials. Don't worry if you're using another package, because chances are that you'll be able to keep up just fine (since what I'm going to be doing isn't at all unique to LightWave). Second, if you're an absolute beginner to character animation in general, I suggest you go Googling and read up on some basic character animation concepts. Going over the principles of character animation could, can and do fill hundreds of volumes, and this series is barely going to scratch the surface with respect to theory. So at the very least, catch up on your Looney Toons and take some notes about what you're seeing. Seriously. But stay away from the ones where Bugs Bunny dresses up as a woman bunny. That's just plain disturbing.

As the title of this series happens to be "animating the inanimate," I'm going to turn you on to several relatively simple character animation techniques as applied to objects that would be, you guessed it, inanimate in the real world. The whole point here is to add life to (usually) easy-to-model, everyday objects. While you might be new to character animation, I'm assuming that you're not new to 3D programs in general, so I'm not going to cover the conceptual aspects of 3D modeling here. But with that said, I'm nonetheless going to devote part one of this series to providing a few tips for you to keep in mind when modeling inanimate objects for character animation.

First, though, let's make a couple of introductions. Readers, meet Ralph the Peanut and Al the Calculator (fig. 1). Ralph the Peanut and Al the Calculator, meet the readers. I'll leave it up to you to figure out which one is which from the picture. Their credentials? Ralph was the star of not one, but two fifteen second TV spots, and Al was the main attraction in a web-based simulation game. They are currently desperate for work, as many of us are in this economy, so Ralph and Al have kindly agreed to help us throughout this series (I'm paying them less than scale, but don't tell the union). Now that we're all best buds, on to the modeling tips.

Figure 1: The stars of our show, Ralph the Peanut and Al the Calculator.

1) There's no substitute for careful planning.
Many of us have fallen into the trap, at one point or another, of succumbing to deadline or budgetary pressures and starting on a project without the benefit of properly thinking things through. And, if your experiences have been anything like mine, any project rushed into production this way is bound to have some serious problems somewhere along the line that make you slap yourself on the knee and say, "If only I had taken the time to plan this out, dag gummit!" So yes, as the bold-faced text said just a few sentences ago, there really isn't any substitute for careful planning.

Careful planning, for the purposes of our discussion today, means turning off the computer, picking up a pencil and a sketchpad, getting a lovely beverage, maybe going outside, and starting to put ideas down on paper. Write out a rough script. Make some sketches. Ask yourself questions about the range of motion your character will need to have. Most of all, don't worry about it if you can't draw to save your life. I was a fine arts major, for Pete's sake, and somewhere along the line I went from being able to accurately draw just about anything to barely being able to get a stick figure down. I'm beginning to wonder if someone else did all the drawings in my college portfolio and if the memories of actually producing them were implanted into my brain through some Total Recall-like procedure. In any event, the process of sketching out characters, no matter if your two-year-old has better stuff hanging on the refrigerator, proves invaluable later on.

2) Model only as much as you need.
Now that you're armed with either a half-filled Post-It note or copious volumes of detailed Leonardo-esque sketches and notes, you'll like as not have a great idea of the characters and situations you'll need to build. If your character is going to "live" in the background of your scene and will be relatively far away from the camera, it's probably not the best of ideas to give it a 250,000 polygon count and cover it with a 100 MB texture map. Conversely, if you're going to have an extreme close-up shot of your character, a jagged model with a blurry texture map probably won't fit the bill. Let's look at Ralph the Peanut as an example.

Figure 2: Ralph in action during his big moment.

After reviewing the scripts for both Ralph spots and blocking out the required shots with the director, I knew that Ralph needed to be fairly close to the camera, but not so close as to fill the entire screen (fig. 2, left). Plus, he was in motion a lot of the time, and with the addition of motion blur to make his movements a little more realistic, he didn't need to be all that painstakingly detailed (fig. 2, right). So based on those requirements, I got to work on Ralph. The progression from start to finish is shown in figure 3, but here's the correlating rundown of what I did to make Ralph a believable peanut:

Figure 3: The many stages of Ralph's development.

  • I started with two low-resolution spheres, turned them into egg-like objects, and joined them in the middle (3A).
  • I smoothed the spheres by turning on LightWave's subpatch feature (3B).
  • I used the point transform tools to rotate, shift, and otherwise randomize Ralph's various cross-sections to have a little less of a uniform appearance (3C).
  • I brought Ralph into the LightWave Layout application, surfaced the model (again, I didn't spend too much time getting the surfacing right here, since Ralph wouldn't be seen that close up), and applied a displacement map (3D).
  • I created a whole lot more polygons by generating out a new model from the displacement map to create the final version of Ralph (3E).

There you go. Ultimately, it's probably more polygons than I needed, but since Ralph was going to be the only CG object in two of the three shots (other than a plane to simulate shadows on the floor), I stayed with it so I could apply the leftover hours to other parts of the project. Total time from start to finish: approximately one hour.

One thing to mention here is that all the different tasks I just listed that took Ralph from jagged spheres to the finished product resulted in a whole bunch of intermediate models. Save these as you go, for a couple of reasons. First, you can always go back to an intermediate stage if things go horribly awry. Second, and more importantly, earlier versions make really good low-resolution models if you need to populate backgrounds and such with what, in this case, would be an army of peanuts.

The bottom line is to aim for what you know you'll need based on your plan, and don't waste a lot of time shooting for perfection when "good enough" will do nicely.

3) Make sure you have plenty of available polygons where you need them.
Again, if you've done your legwork up front, you'll know what parts of your model are going to be doing the moving, and model those parts with plenty of polygons so deformations will be smooth instead of, well, not-so-smooth. We'll turn to Al the Calculator here to help show what I'm talking about.

Al is your pretty basic calculator, but after planning out what was needed from him, I had to make sure that every part of him could move in some way. He needed to twist, jump, bend, stretch, and basically be as flexible as possible to convey a full range of emotions. Once Al was initially modeled (fig. 4), it was pretty clear that I needed to beef Al up with some extra polygons so he would have lots of flex points to make the deformations smooth. If he was left the way he was, all the deforming in the world wouldn't have done much more than turn Al from a rectangle into some sort of trapezoid.

Figure 4: Al started life very humbly. In this baby photo, he hadn't even sprouted buttons yet.

Fortunately, LightWave has a Julienne tool to make this process largely automated. After doing a few experiments, I sliced Al into a uniform grid that gave me the amount of polygons I needed to make him move believably (fig. 5). I could bend, twist, or stretch Al at any point along his surface and there would be enough "there" there to make him do what he needed to do, whether it was lean forward and blink his "eyes" or perform a twisting jump maneuver to express his utter excitement at the user doing something good. Without belaboring the point too much more here, the idea is to try to find just where you need to add extra polygons so you can have your character express the range of motion that it needs to come animation time.

Figure 5: Al's feeling a little more lifelike after a good dose of the Julienne tool.

4) What geometry you do have, try to make it as tidy as you can.
I've never read anything like this anywhere else, so I could be way off base with what constitutes best practices for other designers (or, I could be completely visionary here, which I highly doubt), but over time I've found that the more organized your models are as wireframes, the more predictable they'll be when deforming them. Unwelded points, stray polygons, or other geometric messes might make for seemingly random results when it comes time to animate and render, so any time spent polishing your geometry in the modeling stage might save countless and/or expensive hours of re-rendering or trying to fix things in post later. Again, let's turn to our buddies Ralph and Al for a demonstration.

Figure 6: Ralph and Al's polygons are relatively tidy, considering all they've been through.

Figure 6 shows side view wireframes of Ralph (left) and Al (right), and while both dudes have a lot of polygons crammed into them, they're arranged in a predictable way (at least to me). Al is probably the cleaner of the two, what with me having sliced him into a square grid and all, so whatever deformations I choose to later apply will behave as I expect them to. Ralph is a little less organized, mostly due to the fact that I virtually smacked him around a fair amount to get that wrinkly peanut skin looking just so, but you can still see the underlying cross-sections I started with arranged somewhat neatly. Again, I'll have a lot of options as far as deformations go, and he'll deform smoothly when the twists and bulges and whatever else get applied later on.

Figure 7: Sadly, this little guy wouldn't fare very well after some deformations.
On the flip side, let me go back to a model I used in a review I did of Swift 3D LW 2 a while back, where I have a flat edge of an object that has just been hacked to all hell through the polygon tripling process (fig. 7). There are two problems here: not enough polygons and messy geometry. If I want to apply any deformations to this model, I'm definitely going to get a vertex here and there going completely haywire on me, and the results aren't going to be at all pretty.

Next time...
Hopefully I've armed you with enough modeling information here to get your characters ready to jump right into the different ways we're going to animate your inanimate objects. In our next installment, we're going to delve into the first of three pretty simple techniques to add some believable character motion to your models, so stay tuned...

When not fleeing the paparazzi or spending his vast fortune associated with the fame and notoriety of being a DMN contributor,
Kevin Schmitt can be found with his eyeballs glued to his computer screen, attempting to use some of the hardware and software he rants so incoherently about. An award-winning animator, artist and multimedia producer, he is currently a freelance designer located in the enormously bustling megalopolis of Charlottesville, VA. Whether you're looking to "give him the business" of either the figurative or literal type, feel free to drop him a line. He's ready to believe you!

Page: 1

Though the fame, riches, and notoriety of being a DMN contributor are both tantalizing and substantial, Kevin Schmitt still stubbornly insists on continuing his work as the Director of Interactive Services at EFX Media, a production house located just outside of Washington, D.C. Feel free to follow his updates and contact him through Twitter if you have something to share - he's ready to believe you!
Related Keywords:3D, character, animation, LightWave

Content-type: text/html  Rss  Add to Google Reader or
Homepage    Add to My AOL  Add to Excite MIX  Subscribe in
NewsGator Online 
Real-Time - what users are saying - Right Now!

Our Privacy Policy --- @ Copyright, 2015 Digital Media Online, All Rights Reserved