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Post Processing in Studio Artist
Using autorotoscoping tools on 3D animations

by David Nagel
Executive Producer
dnagel@digitalmedianet.com

We've spent a lot of time of the painting tools in Synthetik Studio Artist. There's still a lot more to cover in that area, but I thought we'd take a detour this week to look at one of Studio Artist's major features—its rotoscoping capabilities.

If you don't have Studio Artist and would like to follow along, visit http://www.synthetik.com.

How rotoscoping works in Studio Artist
When you think of rotoscoping, you probably think of labor-intensive techniques used to remove wires from movie scenes or to clean up mattes or to perform some other technical clean-up job. Or maybe you think of Max Fleischer and his original rotoscope device, wherein an "artist" would trace over the individual frames of a live-action sequence to produce cartoons like Gulliver's Travels or Popeye the Sailor or Superman.

The rotoscoping tools in Studio Artist don't resemble either one of these, although the result is more akin to the Fleischer model.

Studio Artist uses a unique process called "autorotoscoping." Essentially what it allows you to do is to paint over a frame of an animation, and then apply those strokes—uniquely—to every other frame in the animation.

The key word here is "uniquely." If you think about the problem of automating rotoscoping, you realize that to apply one frame's worth of paint strokes over an entire animation results in a very lengthy still frame. In other words, in order to automate the rotoscoping process, a program would somehow have to know magically what it's supposed to do with each new frame in an animation.

That's what Studio Artist does.

In this first installment of our look at Studio Artist's autorotoscoping tools, we're going to postprocess a small piece of animation that I output from a 3D program. You could do this with any piece of video though, since Studio Artist supports any CODEC you have installed on your system that can be recognized by QuickTime.

This particular installment will focus entirely on the automated rotoscoping process. You can also combine manual and automatic rotoscoping or do it all manually, both of which we'll examine in the future.

DEFINITION: We'll be referring to something called "PASeq" in this tutorial. PASeq stands for "Paint Action Sequence." This is simply the list of effects and parameters that Studio Artist will be recording for you as we go along. I'll show you how below.

The goal
For this one, I'm going to take an animation of a skater and make it look as if each frame had been individually painted. In my prep work for this piece, I wound up with two results that I liked, but we'll just take a look at the first one, as I think it's more of a crowd pleaser than the second. Each one started off as a render from Curious Labs Poser 4. I didn't pay any special attention to the quality of the render because I knew I'd be making significant changes in the end, and Studio Artist is both resolution-independent and very forgiving when it comes to the quality of your source material.

NOTE: If you'd like to see these effects in action for yourself, you can download my own Paint Action Sequences (PASeqs) and apply them to your own footage. You can download them here. To use these, just unstuff them and then go into Studio Artist and select Action > Import Paint Action Sequence. In the last part of this article, we discuss how to apply these actions to a movie.

So let's take a look at what we're going to do here. The first two examples below were rotoscoped from the third example below. You can click on the two processed images to see the animations, bearing in mind that compression for the Web has reduced the quality of the output.

 

I'm a fan of both of these. The first one looks something like colored pencil with acrylics, while the second looks like a bad photocopy that's been drawn over with a marker or watercolor pen. These in no way represent the limits of Studio Artist, but let's see how these particular pieces were made.

TIP: In Studio Artist, every stroke of every frame is unique, which requires special considerations. If you use a "normal" frame rate of 24 or 30 FPS, your background will look more like noise than art. So lower the frame rate to 8 or 10 FPS, at the most. You can then remap your footage in a compositing application, such as Adobe After Effects, to run at your desired frame rate.

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