Need For Speed 2015 water droplets

Does anyone know how to apply that wet effect to surfaces (not lenses) like Need For Speed 2015 water droplets on cars? I couldn’t really find anything similar.

I did accidentally make this effect a while ago, whilst trying to get a convincing ‘wet lens’ effect. Water on camera lense effect - Rendering - Unreal Engine Forums

Needs some more tweaking, but I think I got it