Hi all,
I'm currently working on a scene set in dark woods with a tree village that has something like torches to light the walkways. So in order to actually light the village, I cranked up the luminosity of the corresponding shader in the model. That's of course working fine (although I probably have to increase the GI detail some more to get actually consistent lighting). The problem is that the torches show up as really bright and overblown yellow spots in my image with the current luminosity of about 500. Now I know that this is probably realistic but I would prefer something more artistic like in the second picture where the luminosity is set to 0.5 but keeping the rest of the lighting of the first one of course.
Is there any way to achieve this without doing two renders and combining them in Photoshop?
(https://i.imgur.com/BR4H6oSl.jpg) (https://i.imgur.com/tcSqWKTl.jpg)
It probably make sense to see the torchlights. What you could do is put actual Light Source instead. It will look much better and should be faster to render as well. Keep a small radius, something like 0.05 and a small max distance, let's say 10 (depends on how big is your scene)
If I remember correctly you can even turn off the light source itself so you won't have at all the bright spot, only its light on the environment.
Cool scene, it reminds me of the Ewok village at the end of Return of the Jedi :)
Luminosity isn't handled well over point lighting as far as lighting things up and atmosphere.
The atmosphere bloom will help with your light blooms in the haze without the need for cloud layers.
You can duplicate the set of selfilluminating objects and use the first set to visible with a multiplier of let's say 0.5, and the second one with a very high multiplier and make it invisible. Thus you'll have the visible objects looking realistic and the invisible ones casting light without overblowing the camera. You should probably use the path tracer to get a better result. I did that before, and it works nicely.
Quote from: Hannes on January 22, 2020, 11:39:44 PMYou can duplicate the set of selfilluminating objects and use the first set to visible with a multiplier of let's say 0.5, and the second one with a very high multiplier and make it invisible. Thus you'll have the visible objects looking realistic and the invisible ones casting light without overblowing the camera. You should probably use the path tracer to get a better result. I did that before, and it works nicely.
Great idea Hanes, you could actually go way insanely higher in values without any of the effects. Still I wonder how haze is handled. It often gets grainy with luminosity.
I'm not at home atm, but I think, lightsources look way more grainy together with haze than selfilluminating objects.
Worth a test...
Quote from: Hannes on January 23, 2020, 01:27:23 AMI'm not at home atm, but I think, lightsources look way more grainy together with haze than selfilluminating objects.
Worth a test...
Huh, really? Though I believe my testings have been with surface layers on objects (minimal luminosity like headlamps) and light bulb filaments and in general on a surface. Never tried just like a orb or anything. Another issue I noticed is the lighting from luminosity (like glows from windows/lights) also creates weird shapes in GISD. I'm not sure why, where when I'm doing close up stuff I often gotta use a light source to mock the luminosity.
I couldn't get this to work with spheres, especially the luminosity in the v2 haze. Do they need to be important objects or any other special settings?
Luminosity won't affect volumes except through the GI cache. Wich means you will only get a light glow in the volume, compared to proper volumetric shadows with a light source.
Ah OK, no volumetric glow. But for illuminating the surrounding objects it should work.
Yes, especially with the path tracer.
Thank you very much for all the suggestions!
I had considered using light sources but considering the number of lights I have I was really hoping to avoid that so thanks Hannes for your excellent suggestion of using a second object with only the lights. A test of that is rendering right now. And I'll also give the path tracer a shot for that scene.
@KyL This actually is a Star Wars scene as part of my skybox project for the Knights of the Old Republic game. It's the Wookiee homeworld of Kashyyyk.
Quote from: Hannes on January 22, 2020, 11:39:44 PMYou can duplicate the set of selfilluminating objects and use the first set to visible with a multiplier of let's say 0.5, and the second one with a very high multiplier and make it invisible. Thus you'll have the visible objects looking realistic and the invisible ones casting light without overblowing the camera. You should probably use the path tracer to get a better result. I did that before, and it works nicely.
Hmm. My first tests were very unsuccessful. I had either the same glow as before or no light coming from the torches at all.
What exactly did you refer to when you said to make the object invisible. I tried setting the opacity to 0 but that resulted in now glow at all so I assume you were refering to something else that I missed somehow.
There's a possibility in the object tab itself; visible, holdout, invisible.
Oh...
Found it and now I feel a little stupid.
Thank you :)
It's working now! Thanks everyone.
I still have some weird lighting glitches even at higher resolutions, a GI Cache detail of 12 and GI sample quality of 6. I assume that's either due to the very small light sources or due to pretty horrible geometry in the models. Are there any settings that could help improve this? I'll upload an image showing the issue as soon as it is rendered.
I also tried path tracing for the scene but then I get no light coming from my luminous surfaces at all even with a luminosity of 10000 and 144 paths per sample. But since I never used the path tracer before I figure that this might just be another case where I'm missing something really obvious. So any help in that regard would be very welcome.
Luminous surfaces should definitely work with path tracing. Also with settings for GI that high, you might as well be path tracing, your render times are probably not much lower than PT, and memory use is probably higher. :D Also-also, I would tend to go no higher than GI cache detail of 6 or 8 at most, beyond that you get very diminishing returns. Especially with the GI sample blurring, i.e. "blur radius" (however I do *not* recommend turning this off/setting it to 0 :D ).
- Oshyan
This might change in future, but in Terragen 4.4 the path tracer clamps the intensities of samples at 30. It does this to prevent excessive noise. Some things can be sampled brighter than this (e.g. sun glow in atmosphere and specular highlights generating caustics), but in these cases the shaders have ways to spread out the energy to reduce the intensity of individual samples. The renderer can't do this with luminous surfaces, and their intensity will be clamped to 30 when sampled by the path tracer. To get the surfaces to produce more energy you need to make them larger; you need to increase their surface area.
The cache-based GI in the standard renderer doesn't do this clamping, but it's going to struggle with very bright tiny surfaces as well. The larger you can make them, the better.
Quote from: Oshyan on January 25, 2020, 02:43:02 PMAlso-also, I would tend to go no higher than GI cache detail of 6 or 8 at most, beyond that you get very diminishing returns. Especially with the GI sample blurring, i.e. "blur radius" (however I do *not* recommend turning this off/setting it to 0 :D ).
While it's true that very high GI cache detail is probably not worth it, you might be misunderstanding the blur radius. The blur radius is relative to the spacing of the samples, so higher GI cache detail means a smaller blur radius in screenspace, which means you rarely need to change this value.
That did the trick. Thank you very much!
I simply increased the size of the invisible light objects. Now the lighting is much more uniform at a much lower luminosity value of only 25 instead of a few 1000.
(https://i.imgur.com/6pqPJSKl.jpg)
The effect is good, gloomy and mysterious.