Neat little shadow effect

Tzarcon

<div class="IPBDescription">For fans</div>No offense, but... how is that neat?
The shadow is completely black.
You need to make it more transparent.
Try render mode: color
Render amount: 32-64

And if you want to get especially technical, create a texture of or near the size of the original fan, but fade the edges out.  And then bevel the sides of the brushes so you cant see the edges.

ChromeAngel

Merkaba uses a similar technique to great effect in ns_hera.

coil

This works very well (as Merk uses in his fan hive) when the shadow is under water - a shallow pool or something.  It masks the fact that the shadow is a brush.