emission lights not working as needed in cycles or eevee

Question

I have this scene that is finally starting to come together but I can't get the lighting to work properly in 2.79 or 2.80 (Cycles or Eevee). This is what it looks like in the viewport:

I know the dome needs to be optimized.

This is what it looks like in Evee:

The only lights in the scene are emission objects on the windows. I also have an environment texture that I am trying to use for "HD reflections". As long as the environment texture is plugged-in, the lightning is the same no matter how many, how few, or how high/low I set the emission shader:

If I unplug that environment texture, the scene is completely black (except for emission objects) no matter how high I turn up the emission shader:

I have ambient occlusion turned off.

The blender file is attached (or would be, if I could find the "attach" button (where'd that thing go?). Can somebody take a look at my settings and help me figure out how I can get my emission lights to be usable? As it is now, I can't use them to properly illuminate the scene. Thank you for your assistance.

please use https://blend-exchange.giantcowfilms.com/ for attaching .blend files and make sure you have all the required textures included. — rob, Apr 30 '19 at 12:48
"error uploading". Also, I have 133mb of texture files in a zip, what can I try — hatinacat2000, Apr 30 '19 at 13:09
All my textures are 4K, made in substance designer (I was planning to downsize as needed). Any ideas on why the upload for the .blend file is failing? it's only 1.7mb. Could it be b.c. it is version 2.8? — hatinacat2000, Apr 30 '19 at 13:14
Possible duplicate of How to make mesh lights work in Blender Eevee? — Duarte Farrajota Ramos, Apr 30 '19 at 16:40
No, a moderator made the question say "Eevee"; my problem was that my scene had duplicate shaders and I was updating one that was inactive in the scene. Problem persisted before moving to version 2.80 — hatinacat2000, Apr 30 '19 at 21:44

score 7 · Accepted Answer · answered Apr 30 '19 at 13:19

Eevee isn't a raytracer like Cycles - lights, reflections, shadows, etc. are effectively 'faked' in order to sacrifice quality for speed. This means that you can get lightening fast renders but does require some 'pre-setup' in order to get the desired results - by way of light probes.

Mesh lights (ie, Emission shaders) produce indirect light and by default Eevee doesn't handle indirect light at all.

For mesh lights you need to use an Irradiance Volume light probe. The Irradiance Volume is a cuboid which encases an area of your scene. It is not rendered itself but Eevee can 'bake' the contents to measure the irradience (emission) within that section of your scene, applying it to any other parts of your scene within that volume.

Within the Render properties in the right-hand properties panel is an Indirect Lighting section and within that a Bake Indirect Lighting button. Clicking this tells Eevee to analyse the indirect lighting (Irradiance Volumes and other light probes) which it can then use to render the scene.

Rich, I think you might be on to something important for people who are transitioning from Cycles to Evee. It did turn out That the reason the light intensity did not seem to change at all (regardless of renderer) was that I forgot I had 2 different emission shaders in the scene and was only modifying the inactive one. Deleting the inactive shader and working on the other (while in Cycles) allows the scene to render as expected. Thank you for your help, it saved me some time troubleshooting — hatinacat2000, Apr 30 '19 at 14:33

score 2 · Answer 2 · answered Mar 16 '20 at 01:36

2

If you want to properly show the lighting using Eevee make sure to turn on Ambient Occlusion, Bloom, and Screen Space Reflections in the Renter Properties.

Then you don't need to bake the lights.

answered Mar 16 '20 at 01:36

hoss

121
5

emission lights not working as needed in cycles or eevee

2 Answers2