User interface for timeline-based animation
Existing animation programs (Free & non-Free)
- MacromediaFlash is a good non-Free example.
- Ajax Animator is a FUNCTIONAL web-based (ajax) free-software clone of the flash interface, and uses a SVG based format for saving and compiling animations (http://osflash.org/ajaxanimator)
- Ikivo Animator is a good non-Free example producing SVG Tiny animations (http://www.ikivo.com/animator/index.html)
- Macromedia Director prior to version MX had a different interface (http://www.rice.edu/fondren/erc/howto/director.html) which I prefer(ed) over Flash
- QFlash is a FUNCTIONAL free-software mock-up of the Flash 4 interface, which can import SVG files but not edit them. (http://qflash.sourceforge.net)
- F4l is a non-functional free-software mock-up of the Flash 4 interface.(http://f4l.sf.net/)
- Anime Studio, formerly known as Moho (http://www.e-frontier.com/article/articleview/1913/1/793?sbss=793) a non-free example. (Written in Java.) Features skeletal animation (unique bone rigging for 2D) and automatic tweening of vector operations, view screenshot.
- LimSee2 (http://wam.inrialpes.fr/software/limsee2/) is an excellent almost-free basis. (visible-source limited-use license)
- Spalah Flash (http://spalah.sourceforge.net/?p=10) (not to be confused with Spalah CMS) "is a GTK2/GNOME2 based application for generating Macromedia SWF and W3C SVG animations." The GUI is today minimalist but the author is trying to integrate it with inkscape. See http://spalah.sourceforge.net/?p=19
- SMIL 2.1 player: http://www.cwi.nl/projects/Ambulant/distPlayer.html (GPL)
- Bob Sabiston's proprietary animation software http://www.flatblackfilms.com
- Synfig (link) is a film-quality 2D vector animation editor and renderer. It features image morphing between drawings and output animation that is resolution independent both visually and temporally. (GPL)
- Ktoon (http://ktoon.toonka.com/) is a 2D Animation Toolkit designed by animators for animators, focused to the Cartoon Industry. (GPL)
- Jahshaka (http://www.jahshaka.org/) multiplatform QT animation program powered mostly by OpenGL (GPL)
- Powerpoint (http://office.microsoft.com) has an easy but basic interface. No flash killer, but some nice ideas.
- The Tab (http://www.the-tab.com/) Another non-free example that features elegant systems for parent-child animation and a very interesting feature that is designed for pseudo-3D camera moves.
- Pencil (http://www.les-stooges.org/pascal/pencil/index.php?id=Home) vector and bitmap free animation package using Qt toolkit run on Win32 (XP and works fine on wine), and MacOSX. Simple but already powerful basic animation. It uses blender like timeline with multiple layers and Author plan to export SVG.
- SVGDeveloper (http://www.perfectsvg.com/) is a non-free SVG authoring tool with animation support.
- Blender3D (http://blender.org/) is a 3d (eq. vector) animation program featuring key frame, motion curve, path animation using interpolation (IPO) curve editing combining with shape keys and deforming by a lattice (GPL)
- Gimp the bitmpa editor and it's included animation script for gif is really minimalistic and frame based
- Gimp-GAP (wich stand for Gimp Animation Plugin) is a gimp plugin has some good interfaces for managing movments of objects (menu video=>movepath), layer management and apply effects along animation. A powerfull onionskin management, and notions of clip/storyboard, but could be slow in complexe case and slow computers.
- TV Paint is a non-free bitmap based compositing and animation package. It works with a timeline and layers. Notable feature is the onion skin "mixer", which let's you adjust the brightness of multiple frames before and after the current one.
- Toon Boom is a non-free vector based frame by frame anmiation package. It simulates a lot of the tools familiar to traditional animators, such as a dope sheet, field charts and more. Has two modes, one for drawing "cels" and one for placing them in front of a virtual camera in basic 3D space.
Back in the '80's there was a program on Apple IIE (Amiga and MS-DOS too) called "Fantavision". It allowed one to create vector artwork (although I didn't understand at the time that that was what it was called) and animations. It allowed one to create frames of animation where you manually repositioned, recolored, scaled, rotated etc. the objects from one frame to the next. However, it then automatically interpolated frames between the 2 frames (the number of interpolated frames was configurable) such that it create a smooth transition of the object moving from one frame to the other. The effect was very similiar to the "Morphing" effect for raster graphics (popularized in a Michael Jackson video, I believe). That is, the system calculated the trajectory of "Key Points" of the objects from one frame to the next. This process is often called "Tweening" (a term used by Macromedia Flash). Skencil (formerly known as Sketch) supports this functionality and describes it as "Blending".
I guess what I'm saying is that I think a nice interface to create animations would be similiar. So to animate you would do the following:
- Draw the initial SVG Image
- Increment Frame (from say 1 to 20)
- Reposition the elements in frame 20 (including scaling, color changes, adding removing objects, etc, etc, etc)
- System would then calculate a trajectory for each key point from frame 1 to frame 20. Trajectories would be calculated for things like:
- Each "node" of an object
- Transformation Matrix
- You could display/manipulate the trajectories (using the trajectory editor shown above by the original creator of this topic)
- The system would then store the animations using SVG trajectories and the "Key Points" would be the frames you manually created
- So, to create say a 100 frame animation, one might only need to manually create/modify 10 frames and the system would interpolate the additional frames as necessary.
- Also, once the system interpolated frames it would allow you to manually modify the interpolated frames creating further "Key Points" and allow further refinement and interpolation.
NOTE: 3D apps such as blender also use a technique like this, which I think is most widely known as "keyframe animation" or simply "keyframing". However, many such systems tie the keys too closely to actual animation frames, and this creates problems when the frames-per-second rate changes. Particularly in the case of vector apps which are not so low-level as bitmaps and animation frames, I would suggest that frames should be as abstract as possible.
Having key positions in simple percentages of the total animation time might be a better solution. This would also need to be a global/local system, of course: animated objects would have their own animation time specified when inserted into a larger document. A character's walkcycle would end at 100%, but in the larger animation, it would perhaps only be 5% of the total time, yet repeating as the object moves across the screen.
One issue with this abstraction of frames might be that important animation effects do not occur exactly within frames: small things could be mistimed, or simply missed altogether. If you set the frame rate too low, this would be an obvious side effect, so it's not necessarily a problem that Inkscape should try to fix. On the other hand, a few things could be done to ease this. For instance, "snapping" animation events to frames when exporting (thereby slightly altering the timing), or perhaps just warning that certain animation events are not visible at such a low frame rate.
Of course, on the web, with SVG and DHTML, where most Inkscape animations will hopefully be used one day, frames are not an issue at all, and we just worry about keys in time :)
ANOTHER NOTE: Interpolation does not necessarily occur along straight lines and linearly in time. Paths are already part of Inkscape, so points could move along paths; also he time-length graph can be something like a path, instead of a straight line.
I have used jahshaka for a small animation. This was my first real experience with animation. Thought rough, jahshaka is all about key frames and setting properties for those key frames.
Things I liked
- Key frames are on a per object basis
- When an object is selected you can quickly move from one key frame to another
- properties values for rotation can span beyond 0 and 360, permetting to set three or more complete rotation with too key frame. I think this kind of feature could be used for all bounded values (like color, transparency and so on). Is this compatible with SVG or should it be an artifact ?
- representation of properties values on a time line graph. This functionnality was still not very usable, but being to interact through that kind of object could be very useful (see below)
Things that lacks (and Inkscape shall have)
- possibility to copy animation properties from one object to another (say copy color animation, or whole animation)
- possibility to modify a property value for all key frames at once (eg. translation of object for all key frames or a selcted group). I think this could happen through the value = f(time) graph metioned above. You could select points (representing keyframes) and move them up (more), down (less), right (sooner). This graph could be organised by properties set (color, position). I think this kind of graph would be very close to SVG animations tag.
- macro that helps sets common effects (like blinking for example, or crossing the screen....)
Bob Sabiston Example
Bob Sabiston's animation software is an amazing vector-based package that stores line width within the points that make up a line -- derived from a tablet pen. usually in a simple stroke there could be a hundred data points storing width information. Then in the next keyframe, a line from a previous key is selected and re-drawn restricted to the same number of points. The software allow sthe points to be "repositioned" as you watch their previous locations be re-positioned. When you run out, the line ends automatically. This information is interpolated in tweening frames to change shape, width, position, but retains the same number of data-points. See the film "Waking Life" for the making-of video for a demonstration. Also visit his website for examples of it's capabilities converted to flash. http://www.flatblackfilms.com
Suggestion from someone else: working like CinePaint (compared with Gimp), with each frame independently from each svg document (working like this or providing this feature) - providing vectorial edition quality we can't get on apps like Macromedia Flash or any other (maybe ToonBoom or Moho) - allowing us to make our work fast publish without further lack of quality. (One more suggestion about it: being able to convert .swf to .svg sequence (or animated .sgv) and vice versa.)
It is suggested that there be basically two modes: Local (Object) mode and Global mode. Below is a picture showing a very rough design of the local mode:
In local modes, all properties of the object editing will be shown on a timeline, and one can create and edit frame within the timeline. Then one may assign different value of that properties on different timeline, or make it change linearly, or nonlinearly :)
Animation support in Inkscape offers great new opportunities. Here are some points that I think are important to keep in mind when adding animation to the GUI:
Don't do as other do - except it's the best way.
Animation should not stand in the way of the user. Only show as much as necessary to perform a certain task, and do things in the most natural way.
SVG animation is different in some ways. The UI should reflect this, and not reassemble concepts of tools that just work differently. E.g.,
- SMIL animation has no concept of frames. So we don't need a frame-based timeline, but a time-based one.
- SMIL animation in general is to animation what vector graphics is to graphics: It's declarative and object oriented. So one doesn't animate a scene, one animates objects on a scene, etc.
The animation UI should reassemble concepts that Inkscape users are already familiar with:
- Animation timelines can in some contexts be treated as paths that one can add points to (keyTimes). Or one can control animation timing with splines (keySplines).
I composed a mockup that reflects the above mentioned characteristics to some extend: http://www.uni-bremen.de/~felwert/inkscape/Animation01.html
You select an object and add types of animation. These are listed in the custom animation pane. They can be set to occur all at once, one at a time, onclick, with previous or after previous. A number appears next to each object in the editing window when the object has animation applied to it, representing the sequence of the animations. When an object has an Entrance type animation added to it as the first animation, it will not appear on screen until the timeline reaches this point. animations can be linked together to create quite complicated sequences.
Onion skinning is a standard animator tool, previous or next frames (sometime both) are displayed under the current frame with differrent color, or less contrast, allowing to understand wich drawing the animator is actually working on, and wich frame is 1 step or 2 step before or after the actual frame.
This can easily be implemented using transparency parameter of layer, and automatize selection of layers to be displayed, parameters following a specialized gui entries.
Onionskin in gimp-GAP is a good example of what should be a minimal requirement. that is managin backword, forward and both direction onion skin, with variable visiblity increase decrease. Color changes on onionskinning could be another useful option to increase visiblity of different frames, as generally the onionskinning is done at the sketching animation step (meaning mostly grey or black & white drawing)
I have started using svg to develop interactive displays. Having used several other svg tools currently on the market, I am interested in a more generic implementation that doesn't have animation effects get in the way of interactive controls.
Playback of Construction Steps
We, at Class Apart ( www.classapart.org ), plan to use Inkscape in a manner similar to the classroom whitebord to create taught lectures and record the screen in an mpeg movie. The problem is that raster based formats would take about 50 MB for an hour of content, and does not go very well with our unstated goal of getting a whole course on a cd or all courses of a semester on one dvd. It would be great if we could store the construction steps of the svg keyed against time while recording. Then while playback we can patch the svg dom with the steps as needed, using something similar to smil script. How does one go about implementing this? We could find some members willing to implement.
Anime Studio (and all 3D animation software) uses bones to animate with. In Anime Studio you draw up a basic skeleton and then attach the drawing to the bones This is done automatically based on the distance between the bone and the points on the curve. You can then move, rotate or scale the bones to animate the characters. You can store these values per frame, and have the computer interpolate them. This is a much faster way to work than to interpolate the points on the drawing directly. 3D software is probably a better reference here than Anime Studio. Usefull features include:
- Weighting of individual points to bones
- Combining tweening and frame by frame animation. To create replaceable mouths, rotating heads and more.
- Inverse kinematics, to speed up animation. With it you can grab the hand of a character and have the arm follow, rather than rotate the upper arm and lower arm separately to move the hand.
- Constraining. Making one bone follow another, limiting the movement of a bone and so on.
- Graph/Curve editor. A time based editor with b-splines representing the individual move, rotate and scale transformations. This gives the animator great control over the animation.
Toon Boom, Plastic Animation Paper, TV Paint, Animo and traditional 2D animation on paper, all use individual drawings per frame. This gives you by far the best control when doing character animation, but at the cost of a lot of work. Features that are needed for traditional 2D animation to work well include:
- Onion skinning, preferably multiple levels back and forward and adjustable transparency.
- Dope sheet or timeline where you can move frames back and forth and repeat/hold frames.
- Cut-outs, where you move a whole or part of a frame to a different position for tracing on another frame.
- Some way to do rough sketching. Plastic Animation Paper is a good example here, though it's bit map based. With a tablet it gives you pencil like feel when drawing, giving darker lines the harder you press. This helps the animator "find the line". It should be possible to do in vectors if using a central line that stores the pressure along each point (width and/or opacity), rather than an outline.
Combining tweening animation and frame by frame animation can in many cases give the best results.
SMIL Animation (SVG Animation) vs SMIL Timing and Sync
What should the scope of Inkscape's animation capabilities be? Many people are talking about mimicking other software's ability to do frame-by-frame animation and cartoon animation (particularly Flash's).
SMIL's animation module however does not provide for elements to begin or end, although we can fake this by having elements initially invisible, and animating their visibility to 'true' during their lifespan.
While this may be feasible for a few long animations (ie, scenes), will it work for someone attempting to do traditional 2D (even Flash-style) animation? Said hypothetical user, while they may take some advantage of shape and motion tweens, will also likely need to replace the entire drawing when elements of the drawing (characters et al) change their logical structure (a motion requiring a line to appear or disappear). If this is to be supported, Inkscape will need some VERY fast code for switching visibility on-and-off during previewing, as it may be considering the visibility of hundreds if not thousands of graphic elements at a time, to over a dozen times per timeline-second.
Will other SVG viewers be able to handle that, too, or is it a special use of SVG that's not central to the aim of Inkscape?
SMIL's "Timing and Synchronization" module supports elements that allow for massive numbers of sequential images or animation elements, as well as defining animation attributes for begin/end/duration timelines. While it's not part of the SVG spec, would this be something Inkscape should look into implementing, or even proposing as an addition in a revision of the SVG spec?