How to get gradient going up?

[NinjoOnline]

I’m trying to get an effect like this

I’ve tried using the forcefield material, beams, lights, everything I can think of, but can’t get this kind of effect where it’s transparent, and the bottom half is there, and it gradually fades as it goes up

[Kolbxyz (Kolb)]

I think it’s a mesh (blender?)

[sikowwitzz]

I think its an image like this, a gradient with a half transparent background on a normal transparent block