Our team needs to create 2D animations that trigger the ‘perception of causality’ or the ‘perception of intentionality’ through the movement of simple shapes. (Jointed figures with faces and props can come later.) The prototypical example of such animation is the one Heider and Simmel used in their experiments in 1944, since then transcribed into Flash.
I’ve been evaluating animation toolkits with a few objectives in mind:
- Creating such 2D animations must be as easy as possible
- It must be possible to inspect such an animation programmatically to determine where each shape is in each frame. (We are creating a simulation that will “watch” the same animation, but instead of observing pixels it will read such data.)
- The animations must be easily distributed, such as being able to run in most browsers on most platforms using no plugin or only a commonly installed one
Here are my evaluations.
- Flash files (SWF file format) are playable on most platforms using the Flash Player browser plugin, which most people already have installed
- There are many online tutorials about how to create animation using this toolkit, and expertise with the tool is widespread (so it would be easy to find help or hire someone)
- The “motion tween” feature available in the CS4 version eliminates the need to copy/paste/tweak each frame into the next frame; instead, one just drags from the starting position to the ending position, and can add arbitrary curvature at many points in between by pulling on edit points.
- Although it’s a binary file format, the SWF format has been documented by Adobe, and there is an open-source Java library, JSwiff, that provides handy wrapper accessors. It even has a forum for questions about JSwiff, but answers seem infrequent.
- This library is a little out of date, since it refuses to process files using SWF versions after 8, but the code seems capable of handling version 10 just fine (version 10 is what CS4 Flash Pro generates). To use the library with more recent SWF versions, it seems one has to edit the source (included in the download) by changing SWFDocument.setVersion to eliminate the max version check, and then build one’s own jar file. This method refers to private member “header”, so one can’t just subclass SWFDocument and override the method.
- The JSwiff site also offers a separate download for its inspector.bat, which provides a GUI for inspecting all tag content of a SWF. Surprisingly, it works on SWF version 10; I’m not sure how it gets around the version check.
- Note: There is another Java library, JavaSWF, but work on it seems to have stopped around 2005 and it doesn’t handle recent updates to the SWF file format such as the DefineShape4 tag. There is a JavaSWF Yahoo group, but it seems answers are rarely provided for any questions in recent years.
- Adobe’s tool costs US$700.
- There is an option to Export Motion XML, which seems like a good alternative to the Java wrapper, but despite multiple attempts I couldn’t get it to include information about each frame of my test animation.
- At US$50-150, much more affordable than Adobe’s toolkit
- Harder to use than Adobe’s toolkit because they require copy/paste/tweak of each frame of motion, and there is Â no motion guide unless one sketches a path using the drawing tool and then erases that path.
- Toufee’s min frame rate is 1 frame/sec, which is far too slow for my needs. It also has a number of bugs such as having random transition effects on by default, and making it impossible to configure an object to disappear faster than in 5 sec in the first frame
- Although Synfig is an open-source SWF-creating toolkit, which would otherwise make it very attractive, it has such a convolutedÂ install process for Windows that I’m not willing to put my time into evaluating it further. It seems likely that it could just break someday, and there would be too little interest in Windows users to expect them to fix it.
Alternative web-based animation platforms
- Inexpensive (free) toolkits
- Easily distributed and demo’d
- Would require investing significant time or hiring funds into programming animations largely from scratch
- Would require significant effort to design a way that an outside application could inspect what objects are depicted and what is happening
- Free, open-source, and allows for easy creation of motion paths
- Allows export to SWF
- Motion paths aren’t editable — one needs a very steady hand
- Current release won’t run on my XP machine, and on my Vista machine the lasso selection tool doesn’t work, which means I can’t create any motion paths. Not actively supported right now, but that might change soon.
Bottom line: Assuming one can afford Adobe’s Flash toolkit, the combination of it and the Java wrapper seem like a very workable solution.