I also saw what The Jamsh and DieByZer0 have mentioned here on the forums, Trying to get particle shadows to apply to other particles. - Rendering - Unreal Engine Forums, but I would mention that you want to make sure that depending on your normals you can increase their influence with the Translucency Directional Lighting Intensity which would help a little. For the task you mention on the forums. You probably will want to look into MacroUV to achieve the look you want but it will be an effect applied to the particle system which will emulate the look you are wanting to achieve.