High luminosity without overblowing the camera

[Kexikus]

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.

[Oshyan]

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. 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 ).

- Oshyan

[Matt]

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.

[Matt]

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 ).

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.

[Kexikus]

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.

[gao_jian11]

The effect is good, gloomy and mysterious.