Is there a way to give an emissive light source a decay effect?

VidRyan

This is a bit complicated, but I've been trying to create a sort of sonar effect similar to Daredevil or Toph from Avatar: the Last Airbender. The idea being that a character is able to sense the environment without relying on sight, and I'm looking for a way to visually represent that. One of the ideas I have been tinkering with is creating a spere primitive and turning it into a ghost light with an emissive shader. I would then be able to animate the sphere expanding outward and illuminating the environment as it passes over and through it. The problem is that emissive light is either bright enough to illuminate everything, or else it's so dim that it hardly illuminates anything. Ideally, I want a tight band of relatively bright light that sweeps out across the scene. I've been told elsewhere that the effect I'm trying to create might be impossible, but I would like to exhaust all potetial options before coming up with an alternate way to visualize this effect. I've thought about nesting a sphere inside another sphere so that it creates a sort of light shell, but I don't think that's possible either. In order to block the light from passig through it, the outer sphere would need to be opaque, which defeats the purpose entirely. I'm open to any sort of suggestions that might be helpful in resolving this sticky situation. I don't mind buying some specialized shaders or similar, so long as they produce the desired effect. Thanks for readig this, and for the assistance :)

crosswind

Sounds like you need a sort of godrays, i.e. volumetric light...

If so, you may either consider using some products like 32459, 56881, 88975..., and / or go for a post work by using some brushes like https://www.daz3d.com/rons-light-radiance. The latter may even give you much better VE on a static render.

johndoe_36eb90b0

Perhaps something like this: