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Installation and User Manual (continued)

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Animation

From the ‘Animation’ menu you will be able to do animations.
At this point you are limited to setting, showing and deleting markers, showing the trail derived from these markers, and doing a smooth animation moving the screen along the trail. You can also save and load an animation.

Example

Let us start with an example.
Choose the ‘Open…’ menu item in the ‘File’ menu and choose the ‘city.ttp’ tree file from the ‘trees’ directory. Then choose the ‘Load…’ menu item in the ‘Animation’ menu and choose the ‘swirl.taf’ animation file from the ‘animations’ directory.
Finally, choose the ‘Start’ menu item in the ‘Animation’ directory.
You should now see a nice animation.

Creating your own animations

By choosing the ‘Control’ menu item in the ‘Animation’ menu you toggle the animation control dialog.

the animation control dialog

Saving and loading animations

By choosing the ‘Save…’ and ‘Load…’ menu items in the ‘Animation’ menu you can save and load your animations, respectively.
The first time that you choose ‘Save…’ or ‘Load…’ the ‘animations’ directory is shown, but of course you can put your animation files anywhere you want.

Another way to create your own animations

An animation file contains all the definitions for the marker points that make up an animation.

Before we look at the structure of this file, let us first delve deeper into what constitutes a marker point.
So a marker is a vector p somewhere in 3D space and it has an orientation or orthonormal base which tells us how the screen is positioned. The orthonormal base is defined by three vectors u, v and n.

a marker point

An animation file contains all this information. Actually, an animation file is a file that conforms to a set of simple rules:

The file ‘swirl.taf’ from the example above is a valid animation file:

! animation file for The Tree Project
! see www.jogja.nl/manuals.html for details on the structure of this file

! [MARKER] p_x p_y p_z [U] u_x u_y u_z [V] v_x v_y v_z [N] n_x n_y n_z

[MARKER] 0.0 0.0 0.0 [U] 1.0 0.0 0.0 [V] 0.0 1.0 0.0 [N] 0.0 0.0 1.0
[MARKER] 350.0 500.0 1750.0 [U] 0.0 0.0 1.0 [V] 0.0 1.0 0.0 [N] -1.0 0.0 0.0
[MARKER] -150.0 1000.0 3500.0 [U] -1.0 0.0 0.0 [V] 0.0 0.0 -1.0 [N] 0.0 -1.0 0.0
[MARKER] -650.0 500.0 1750.0 [U] 0.0 0.0 -1.0 [V] 0.0 1.0 0.0 [N] 1.0 0.0 0.0
[MARKER] 0.0 0.0 0.0 [U] 1.0 0.0 0.0 [V] 0.0 1.0 0.0 [N] 0.0 0.0 1.0

Although we now know the simple rules to manually create a valid animation file, for the file to be useful we must ensure that u, v and n form an orthornormal base with the same orientation as the positive parts of the x, y and z axes shown on the previous page.
Mathematically that means:

If these conditions are not fulfilled then results may not be as desired. The simple example above of course satisfies these conditions. But it requires a bit more effort to manually construct an orthonormal base which is not just 'ones and zeros'.

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