Overview of 2D animation programs

Pencil

Pencil  [7] is available for download in the package sources of common distributions. The project provides a well-structured and easy-to-understand guide  [8], but this software also is not the newest. The latest version is dated 2008, but the programmer recently announced that he has resumed development of a new version.

In Pencil, animations are edited on four layers: bitmap graphics, vector graphics, camera, and sound output. Each of these layers has its own timeline, so you can set what will be shown when for each output layer.

In the bitmap layer, the standard instruments (e.g., pencil, line tool, or paint bucket) are available for drawing images. Beyond that, you can import external graphics files. Interestingly, the vector graphics layer uses the exact same toolbox (Figure  4). The only difference is that the software saves the images as vectors instead of pixels, which does not always work well when using the paint bucket to fill in areas. The camera layer defines the visible part of the image for each point in time. Variable background music is set using the sound layer.

Figure 4: Pencil is used like a paint program but has additional timelines.

One possible animation strategy is to draw a bitmap graphic first, trace it as a vector graphic as soon as the desired end result has been achieved, then subsequently add colors to the result.

If you want part of the drawing to change during animation, you have to make this happen by hand. Pencil does not support tweening, so you have to copy the graphic to the next frame; even the smallest change must be drawn by hand, which takes a lot of time. Even if graphic artists sometimes claim that professional-looking 2D-animation films require that each frame be drawn by hand, some automated support through tweening would still be welcome.

Pencil scores well mainly because it is intuitive and easy to use. The instructions are easy to understand and concise. Altogether, the program makes a good impression, but it's too bad that it does not include tweening functionality (Figure  5).

Figure 5: The limited functionality of Pencil makes it very easy to use.

Synfig Studio

Several years ago, Robert Quattlebaum authored the Synfig Studio  [9] animation software and tried to sell it. When commercial success was still not in sight by 2005, he published the source code as an open source product under the GNU Public License.

Since then, the community has continuously developed the software so that new updates appear regularly. Complete packages of the current stable release are available on the Synfig homepage for most popular distributions  [10].

The detailed and easy-to-follow instructions are completely in English [11]. While becoming familiar with the software, the focus on tweening becomes clear. Basically, you select key frames on the timeline between which the object is to change.

Additionally, the tweening techniques in Synfig Studio make it possible for graphics to morph into each other. You should plan a sufficient number of frames for this process so that the results will not look too artificial.

Each graphical object in Synfig Studio is its own layer, which can optionally interact with other layers – for example, with appropriate effects when they overlap.

The tools for creating graphic objects are similar to those in popular vector graphics programs. However, the program is not one large main window, but several independent windows distributed over the desktop (Figure  6).

Figure 6: Synfig Studio consists of mutually overlapping individual windows.

Once you have become familiar with Synfig Studio, you will quickly learn to appreciate the program. Although the learning curve is steeper than for Pencil, the instructions prove to be very helpful. Furthermore, the program is also enriched by its functionality.