UNREAL UE4 - How to create a material for a cone shape to simulates a volumetric light?

Hi, i saw a video from someone that instead of using volumetric lights, to optimize the scene, created a normal light, then to simulate the effect of a volumetric light, added a cone applied a material that makes the cone look like a volumetric effect, But i wonder, how how to create this material, its like a ramp from white to black i guess, with transparency to make the black transparent, like the light loosing intensity, this cone looks exactly as volumetric light.

Please share BP images for help, thanks!