I have been trying to process something in this Eevee lesson...What is a mesh light and what is a lamp? Says that HDRIs and mesh lights aren't good for use in a scene, the shadows turn out blotchy. Use lamps. Sun Lamps? Is he referring to Cycles and just didn't say Cycles? I am throughly confused about this.
Hi wrongwright ,
I can't explain it like you're a 6 year old, sorry (I don't know enough abou EEVEE), but a Mesh light is a Mesh (a bunch of points in space (Vertices), connected by Edges and Faces), with an Emiisive Material (Emission Shader, for instance). An HDRI is connected via a Background Shader and that is also an Emission Shader. Emission Shaders do not light other Objects (and thus casts no shadows) in EEVEE, but are just glowing a bit. But they can affect Light Probes and cast shadows via indirect light (I don't know how that works, sorry).
A Lamp (nowadays called a Light in Blender), is one of four types; Area, Point, Spot or Sun and does light other Objects in your Scene (and therefor casts shadows) in EEVEE.
Everything that is said here is about EEVEE, lighting with Cycles is covered in last Chapter.
Eevee works different than Cycles, but not by much, it's just that Eevee fakes everything. Lamps are the same, sun lamp, spot lamp, etc, they emit light no matter the render engine, but Eevee uses a different method, just like JL explains. So try to think of it same as you do for Cycles, but Eevee is like a hacked version and it makes it faster to render in real time.
But it's impossible for us to condense Eevee in a single post here, if you don't understand anything, don't be afraid to go back and watch several times, while you put it to practice with Blender open, trying stuff out.
Basically Cycles does everything for you, you don't have to do much, but in Eevee you have control of settings and it's more technical. Things that Cycles do for you for free, you have to tell Eevee to do them for you. Such as shadows, Ambient Occlusion, reflections, bounce lighting, etc.
HDRI was several lessons ago, it was turned off since first or second lesson. Anyways, end of your first paragraph might explain some of my issue. I understood HDRI didn't cast shadow but affecting light probes...perhaps. I can get onboard with that (edit) but HDRI was turned off. Just the other lights causing problems then, just not sure what the other lights are if not Area, Point, Spot and Sun. I don't remember any prior lesson talking about Mesh Lights as a source. It's been either Area, Sun, Spot and Point was added later.
so we're calling all the light (shapes) Lamps? as in Area, Point, Spot and Sun. Ok good. Just seems like "HDRI and Mesh light" are coming out of left field for me. I'll leave it be. Maybe the end of the lesson will make sense. I've only just seen it once at this point. I need to see it again, a few more times.
Thank you
Hey wrongwright ,
Did you skip the Lighting with Cycles Chapter, by any chance?
The first Lesson is: "The 7 Ways of Creating Lights". Mesh Lights are also covered there.
Didn't skip anything, if fact will probably rewatch the Eevee and probably a few YouTube vids for variation sake. (edit). Having rested a bit , I went back to the lesson with a clearer head. I now believe I've grokked the beginning of the video. I'll pledge now never to use HDRIs (for indoors at least) and Mesh lights to light an Eevee scene. Just lamps and some well spaced probes. :)
In Blender 4.2 HDRI's at last can cast shadows. Linking up:
Glad that got cleared up, thanks Martin and Omar! Part of the confusion is probably the fact that I accidentally said 'lamps' instead of 'lights', which is what the object type used to be called back before 2.8 👴
We do talk about mesh lights in one of the first lessons, though it is super brief (and I accidentally say lamps again): https://cgcookie.mavenseed.com/lessons/the-7-ways-of-creating-light