Draw a mesh in "Scene", and "Game" tab, before "Playing"?

I know that by adding the OnDrawGizmosSelected() / OnDrawGizmos() methds to a MonoBehavior inherited class I am able to draw "Gizmos" during the Scene editing phase of the project..

But, what I wanna do is the same as Unity3Ds' particle system. Somehow it is not only able to preview in motion when the GameObject is selected, but also preview statically when the game object is not selected. It also some-how renders this in the "Game" tab to see how it would look in game(from the cameras perspective.)

So please, I hope someone has some insight on how I might do this myself.

I'm working on my own particle system of sorts, and do not want to have to press "Play" every-time I make some modification to the code, in hopes it looks better. I also believe this would be faster than creating a new GameObject every-time I need to render an individual particl.

So this information should definitely secure some of the speed I so desperately need. If anyone out there has any information, please let me know! screams at unity

you can add the ExecuteInEditMode to any script and then the script's Update, FixedUpdate and OnGUI methods will execute in edit modes too in C# you should use a syntax like

public class a : MonoBehaviour { ... }

the documentation page has a javascript example.