For as long as I can remember, I’ve never been able to get emissive materials to actually emit light.
Any ideas?
It also doesn’t help that any tutorials for it are usually 3+ years old.
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i would also like an answer to this. Did anyone come up with a solution?
Well, the emissive part of the material doesn’t actually emit light, despite its name. It’s the part that doesn’t respond to the lighting and shadowing and therefore usually looks brighter than everything else. It’s brightness can be controlled with the emission exposure and can be visually amplified by the bloom effect which creates a sort of halo that emulates the effect of the lighting leaking onto other objects that you can observe in real-life. But there’s nothing more to it, if we’re talking about realitme.
Now, if you bake your lighting, then the emissive mesh can indeed act as a true light source. It can also impact GI through SSGI or ray-traced GI, but it still won’t cast shadows that way.
All in all, you can’t just set the emission to a non-zero value and expect it to affect the surroundings like it’s a true light source, unless you bake your scene.
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Ruchir & passeridaepc make the main points here.
Emissions require the global illumination pass to show the bounce lighting.
If you’re using realtime GI solutions like Enlighten, SSGI or raytraced GI you should see this dynamically update.
Otherwise you’d have to bake it there.
you also need to consider the lighting EV of your in real world units as well.
For example 300nits for a phone screen you’re barely going to see that illuminate in the real world, unless you’re in the shade, the same should apply in game too if you want to stick to a physically based anchor.
If you plan on using emissions for art like magic in the daytime, you may need to tweak these kinds of things and reference a light source that would potentially work in the daytime, or just break physically based anyways cause magic
Just for anyone browsing this thread in future, if you want something like emissive magic particles to glow in non-physical way such that it’s consistent in all lighting condition, you could try adjusting the “Exposure Weight” in the emissive section (For shaderGraph use the emission node supplied with HDRP).
I have seen a lot of people don’t really know that HDRP emission have exposure control for situations like this 
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Ye, I love the new HDRP nodes. I just wish you could use them with both URP and HDRP render targets active 
Know this is an old post, but sometimes exposure post processing can have an affect. Lower this and emmisive maps may appear to work!
you are a life saver
OMG saved my life! 