Blender Version: December 19, 2007 compile (svn experimental)

Tutorial Version: December 19, 2007

Resources: none

Credit: This tutorial is entirely by LGuillaume.   LGuillaume's original tutorial    (With minor updates by myself).

1. How a Harmonic Effector works:

To use harmonic effector, you need an emitter mesh and at least one harmonic effector mesh.

To demonstrate this effect, I will make a little scene to say 'Thanks Jahka" ;-) .

2. Setting up the Scene:

The scene consists of a plane, which emits the particles, and 2 text meshes: 'Thanks' and 'Jahka'.
Tip: You can add the second text object a little faster by simply duplicating the first one and then editing the text.

Note that the new version of Blender adds objects aligned to the Global co-ordinate system, irregardless of which view you are currently in,
and also remains in Object mode when the object is added.
If you would prefer to return to the previous behaviour, activate the buttons 'Switch to Edit Mode' and 'Aligned to View' beneath the
'Add new objects:' header located in the Information Window > [Edit Methods] section.

2_1. The Emitter's Settings:

Nothing special here, add a particle system to the Plane and give it an initial speed with the Normal button in the Physics panel.
Add a Random value if you don't want the particles to have a linear motion.
The most important settings are the End: and Life: values in the Particle System panel.

The parameters which have been modified are outlined below:

2_2. Filling the First mesh: 'Thanks'.

If you haven't already converted the font to a mesh, select the font object, press [Alt] + [c] , and select the Mesh option.

Create a particle system for the 'Thanks' mesh.

Set the Type to Reactor.
Press the Sta/End button. We want to attract and fill the 'Thanks' mesh between frames 30 and 80, so set the value for Sta: to 30 and End: to 80.

Finally, enter the name of the mesh particle emitter in the OB: text button. If you haven't changed the default name assigned to the Plane object, it should be 'Plane'. (Remember that the entry is case sensitive).

Switch to the Physics Subcontext.
In the first selector box, select the particle system 'PSys.001' since we will be using the particles emitted by the 'Thanks' text to attract the Plane emitter particles.
In the Field Type selector box, select Harmonic.

To set how strongly the emitter particles are attracted to the 'Thanks' emitted particles, set a fairly high Strength value.
Depending on how quickly you want the particles to "settle", also set a suitable value for Damp.
You may need to tweak these values to get the desired effect. Also, it's a good idea to set the visualization for the reactor particles to something different
(such as 'axis' or 'cross') so that you can distinguish between them and the emitter particles.

2_3. Filling the Second mesh: 'Jahka'.

The procedure for filling in the 'Jahka' text is pretty much identical for the previous step.
Simply adjust the Sta:, End:, Strength, and Damp parameters to obtain a good result.

3. Final words

Since we don't want the reactor particles to be rendered - their sole purpose was to attract the emitter particles;
in the visualization panel set the visualization mode for the two text mesh objects 'Thanks' and 'Jahka' to None.

Also, because we don't want the original text objects to be rendered, leave the Render emitter button OFF.

Since we're using a fairly high particle count to fill out the text, the default halo material will tend to produce a "blown out" result.
So set a material for the particle emitter of type Halo and reduce the Halo Size to about 0.1 or less.