Had a hard time looking for how to create emissive lighting. Conflicting post making it even more
confusing. So here is my post on the subject with images.
Ok once and for all these are the steps to produce emissive static lighting in UE4. It is available in
version 4.10 which I am using at the moment running on nvidia GTX970.
Turn on Use Emissive for static lighting. Hit Build button to regenerate your lightmap.
Your emissive object should now cast light into the environment as shown in my viewport.
It’s frustrating how easy steps are often not shown with a few images
and mixed posts with conflicting solutions … or false solutions and time
wasting comments.
Side Notes:
The dynamic emissive type (LPV) is still a test model, it has lots of artifacts and typically not
useful for production pipeline … not unless you are a programmer / developer looking to
improve it.
It’s been said before that this method is a pretty expensive way of lighting your scene. Think of emissive material more like a post-effect that simulate the effect of a light buld or neon. You can add a spotlight or point light near the object to emit real light and it’s going to be cheaper to compute!
LPV wasn’t developped by Epic but by Lionhead studios for their game. They just made it available for the public for some reason. There are little chance we see an improvement imo. It’s still in alpha I think?
This is a great technique if you have a digital clock and you want it to illuminate the table it’s on, but to light a scene I think would be expensive. Also, the shadows and so forth wouldn’t be great.
Btw info on how to set it up was released here (same thing as hawkenfox explained)
This is a Lightmass feature, nothing to do with LPV. Has no impact on build time, but small bright emissive spots will cause splotchy artifacts unless you jack up IndirectLightingQuality.
Yup that sounds good for baked emissive and having the multiplier is the most important thing in the shader/ parameter so you can easily adjust the emissiveness.
As for dynamic emissive GI I think LPV just doesn’t quite work, VXGI (and similar) dynamic emissive is much better:
The only problem with VXGI is it’s pretty expensive and isn’t feasible unless you have a GTX 970 or above, and is only supported by Maxwell architecture (meaning only on Maxwell NVIDIA GeForce GTX 7XX cards, 8XX and 9XX cards, AMD isn’t supported and Kepler cards or previous aren’t supported either). DirectX 12 supposedly makes it cheaper, but it’s still an expensive GI method. AHR, or Approximate Hybrid Raytracing, is another GI method that RyanTorant is developing. It looks about equal to VXGI, but performs 3x better on a GTX 750 Ti, according to Ryan’s posts. On top of that, it’s card and vendor agnostic, so it should work on any middle-class graphics card. And it supports things like ray-traced reflections (albeit at a lower quality than SSR and scene captures, but come on, dynamic ray-traced reflections!). Unfortunately AHR is only available as an entire engine branch, so you have to download the AHR branch and build it separately.
