I would like to achieve the same kind of effect that the one in this video with nparticles. I would like to know if someone knows how to achieve it with nparticles. Iam using maya 2009. Tanx in advance.

	Video

I’m not sure you need to use particles for that.
I once made a stroke animate along a curve.
The stroke had a funky style, of which you can edit and add a blur/glow effect - which could result in a similar output to what is in that video.

Obviously this was created in only 2 axis, but it can be done in all 3. You would just have to create multiple objects/curves, a nice shader with glow, and probably render with Mental Ray.
Some post production in AfterEffects may come in handy as well.

	Video

I agree with joed, that this kind of effect would not be based around particles.
You could definitely add some particles to the piece to make it look “cooler”.
But I would suggest starting with a curve of the path and animate an extrusion along the path.
Following up on Joed’s suggestion, good use of shader glow can give some pretty solid results...with a bit of tweaking.
Maybe try applying a Ramp Shader (not Ramp Texture) to the surface. This is a great shader for making weird glowing/ghosty things. Change the Color Input to “Facing Angle” and start adjusting the different aspects of the shader. (Seach MAYA HELP for info on how to use the shader if you get lost) This is something I would suggest adjusting using IPR, to see just how the settings affect the final result.
When adjusting the Glow Intensity try checking the “Hide Source” button...this hides the surface but keeps the Glow.
Also, with shader glow, try adjusting the shader glow globals, which is the shaderGlow1 node found in the materials section of the Hypershade. This can open up a lot of great effects.
***big note*** uncheck “Auto Exposure” if your glow flickers when you you render the animation.
To get your n-particle fix you could use the surface you’ve created to emit the particles.
You will want to animate the emission rate as the surface grows, as a larger surface needs more particles to cover it. While you are working keep the emission rate range low (from 500 - 5000) so that your computer doesnt slow down too much. When you have it set up then change the emission rate (probably at least 1000 - 10,000) for rendering.
The big thing is that the particle lifespan should be really short so they will just create a clound around the surface.
Change the particle render type to Blobby Surface and apply the cool Glowy Ramp Shader you made.
Then just hide the emitting surface and render away.
All the best with the Reel!
~Ben