| Unit 13. Motion Animations (I) |
| It is important to emphasize that to correctly execute a tweening motion the involving objects must be converted to symbol previously. You should also be careful when making a tweening with two symbols that are in the same layer, since the animation motor will group them as the only one and the result will be unexpected. By this it is advisable to make sure two issues:
Let's proceed to the theme in question. A tweening motion, as we've said, is the displacement of a symbol from one to another point of the stage. The fact that only two frames are needed is because Flash, only with the starting point and end point, "knows" the path in straight line and represents it (we'll see that also no rectilinear movements can be made). When we do the tweening correctly we will observe a sign like this in the timeline.
This indicates that the animation will change the position of the symbol of the frame 1 to the position of the same symbol in the frame 20, using exactly 20 frames. The number of frames that are used in the tweening motion will indicate the substages of the animation. The more substages you add, much more vivid will be the sensation of "continuity" (lesser abrupt jumps) but simultaneously lesser its speed in the movement. We
can also change the speed of the motion in the movies by modifying its value in the
time bar,
The rate is expressed in Frames Per Second (pps) and it can be modified by double clicking in the indicated place of the time bar. The larger value, the higher speed will be. But to develop the animation as we want, enough frames are always to be set. Here
you can see how to tween motion
If the object with which we want to motion is not converted to symbol we’ll find something like...
... and the animation will no't work. Also we can make the tweening in another way, without converting the object to symbol previously, since Flash will automatically convert it to symbol if we don’t do it, giving the name "Animate" plus a number. It is enough to right click on the frame that contains our object (in the timeline) and select Creating Tweening Motion. Create a keyframe in another place of the timeline and the tweening motion will be created automatically, and we will only have to modify this last frame to produce the animation. Perhaps this isn’t most advisable in large movies, as we've already commented, because of the large amount of symbols that can appear and confuse by many symbols with similar names. Flash also allows us to create animations with rectilinear trajectories in several phases, with different directions. For it, once the tweening created, it is enough to select one of the intermediate frames and create a new keyframe. If we move the symbol in that frame to another place of the stage and play the animation, it will go first to this position and then to the final position. If we do this several times on various frames we’ll obtain several consecutive trajectories more. In order to understand better this concept we recommend to do the Exercise Processing Tweenings.
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This is very simple with Flash MX; it is enough to modify the symbol instance in the last frame of the tweening motion, but this time changing the size. We can apply both effects simultaneously, so that the change of size will occur while the object moves. Also we can do the change of size in several phases or sequences chained as in the common motion tweenings. The following example incorporates these three characteristics of the Tweening Motion of Flash MX.
And the timeline what's left is something as simple as this:
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