Animation is one of the less-known features in OpenOffice.org Impress. Its most obvious uses are for transitions for individual objects on a slide (rather than for the entire slide), or for dramatic emphasis and calling attention to objects. But it can also be used for more serious purposes, such as illustrating a procedure that is clearer if you can see it in motion -- for instance, one of the most effective animations I saw showed was on a Society for Creative Anachronism site that explained how the links in chain mail fitted together.

If any of these purposes sound useful to you, then you should take the time to investigate the two means of animation in Impress: The Animation dialog window opened from the Insert menu, and the Custom Animation Pane. Both work on any sort of visual object, including imported pictures, shape primitives, or graphic text, although obviously some objects are more suitable for certain types of animation than others.

Despite its name, the pane is for those who prefer OpenOffice.org to do most of the work. By contrast, the Animation dialog is for those who prefer to build their own animation. The two systems cannot both be applied to the same object, although you can use both on the same slide with different objects.

Using the Animation dialog window

The Animation dialog is the most basic way of creating an animation in Impress. It lacks the built-in animation effects of Custom Animation, but it is easier to use for simple animations.

Before you start to use the Animation dialog, create or import all the objects you will use in the animation. When all the objects are ready, select them all, then click Insert -> Animated Image to open the Animation dialog window. Annoyingly, the controls in the window are not labelled, except in the mouseover help, but that should be only a momentary distraction.

Your first step is to click either the Apply Objects Individually to create a separate animation frame for each object you selected. In effect, this choice makes each object a frame in the animation -- and, as with any animation, the more frames you have, the better it will tend to look. There is also an Apply Object button that creates a single frame from all objects, but, to be honest, I have yet to find a purpose for it.

Similarly, although you can choose Group Object under Animation Group in the window, the only choice that seems useful here is Bitmap Object.

From here, go to the top of the controls in the window, which serves as a very simplified timeline. The Image Number field, you notice, shows the number of the last frame in the animation. By changing the Image Number, you can set the Duration to display each frame individually. You can then finish by setting the Loop Count; it is set by default to Max, which mean infinite looping, but have mercy on your audience and choose a much lower setting unless you are planning a display that will run unattended.

Having set the timing, click the Create button, and the animated .GIFs is added to the center of the current slide. From there, you can move it exactly like any other object. You can also delete the original objects, which you don't need any more.

Using the Custom Animation pane

The Custom Animation pane helps you to create a piece of animation using default motions supplied by OpenOffice.org. It is usually in the Tasks column on the right of the Impress window. If it is not, then you can open it by selecting Slideshow -> Custom Animation from the menu, and use the arrow on the left of the pane's title bar to expand or collapse it. The pane is easier than the dialog to use, and its effects add considerably to the complexity of the animation you can quickly produce.

As with the Animation dialog, begin working with the Custom Animation pane by creating or importing the objects that will feature in the animation. When you are ready, select the first object in the animation and click the Add button to open a dialog window.

The Custom Animation dialog allows you to apply dozens of different types of movement to the selected object. For convenience, these types are divided by tabs into different ways for the object to enter or exit the slide (Entrance and Exit) , to call attention to the object (Emphasize), or to move on and outside the slide (Motion Paths). Each tab is further subdivided into categories, such as Basic, Exciting, Moderate, and Special. If you chose a Motion Path, it displays on the slide, where it can be resized or repositioned by selecting it and dragging on its selection handles.

By clicking the Automatic Preview box, you can test animations without leaving the dialog window.

Once you have clicked the OK button to set the effect, you can fine-tune it in the Effects sub-pane. Note that the name of the sub-pane and what you can select in its second field changes with the selected effect. However, you always have three choices:

• Start: Choices are On click (of the animated object), or With Previous or After Previous -- that is, in relation to the previous animated object.T o start the animation of the object as soon as its slide opens, select With Previous.
• Property: Although the choices here vary with the selected effect, if you click the Ellipsis button (. . .) to the right of the field, you can always choose effect and timing options. On the Effects tab of the window opened by the Ellipsis button, you can set the object to dim or hide after the animation is over, add an accompanying sound, or, if the object is graphic text, set animation specific to text. From the Timing tab, you can set individual details of the effect, as opposed to the entire animation, how many times the animation repeats, and whether an object that moves returns to its original position when the animation is done. You can also what triggers the effect, and when it is triggered
• Speed: This setting refers to the animation as a whole, and not any applied effects. Regardless of the computer, you will probably find any speed setting except Fast and Very Fast sluggish and jerky. However, you might have reason to endure these limitations, such as matching the speed to your spoken explanation of the animation.

When you have finished with the first object in the animation, selection the next object to be animated, and repeat the steps. Select an object in the sub-pane, and you can alter its position in the animation sequence by using the up and down arrows.

Conclusion

As you work with these two animation tools, remember than both are far from precision tools. In fact, animated .GIFs are rather old fashioned. Neither is intended for full-fledged animation, and,if you decide to use them, be prepared for a lot of trial and error until you get things exactly right.

In addition, remember that, like any special effect, animation is easy to overdo, especially if you have just discovered it. Unless you exercise restraint, animations can easily distract and annoy your audience -- like a blink tag in HTML, only much worse. Regardless of the tool you use, think twice before using any piece of animation, and, if you go ahead make sure that it stops or at least dims or hides instead of looping endlessly.

Keep in mind the limitations of Impress' animation tools, and they can enhance your presentations the way in which they are intended. Forget them, and don't be surprised if you have an audience revolt to handle.