Hi WAS,
My goal is to give everyone a better understanding of how TG works. So I want to separate what's better about glowing clouds from what's actually the same as with glowing objects.
Quote from: WASasquatch on April 25, 2018, 02:19:12 PM
They may act the same way at the base code level, but what is iterated through each element is a totally different effect.
Perhaps we are talking about different things. I was just talking about how light from the stars affects any surrounding cloud using GI, not the shape of the stars themselves. Are we talking about the same thing?
GI isn't good enough to light the surrounding cloud at very short ranges, but at longer distances away from a big star or a cluster of bright stars it could be useful, and that's what I thought you were trying to do. If so, it really is the same whether you use a glowing cloud or a rock population. It may seem different in my example because I didn't spend time making the rock population look the same as your cloud. Generally 'matt 01' and 'matt 02' are not good scenes for demonstrating how well this GI method could work, because with 'matt 01' I was trying to demonstrate that the GI is of similar quality regardless of whether you use clouds or rocks.
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We have already added stars to our nebulas/galaxies via clouds, and they work, actually very well. Light being cast doesn't go on forever at appropriate intensities, etc. With your example, you can plainly see the graining discussed, as well as the actual lighting artifacts. It also appears your light sources aren't actually coming from the objects in the first example.
Yes, that's true. In 'matt 01' I used a blue-ish cloud to demonstrate the problem that I thought you were talking about. I agree it doesn't look good. You can clearly see that some voxels are not receiving light, and the voxels are too big to ever make this look good. I was trying to demonstrate that it's the same problem in both cases. If you render 'matt 01' with the cloud-based stars enabled instead of the rocks, you will see the same blocky lighting as with the rocks.
But now I think I understand that you weren't trying to generate GI at all, is that correct? Maybe I was sent in the wrong direction because previously you were trying to do this with tiny glowing rocks.
For short range lighting, you either need real light sources or you need to simulate the correct inverse square falloff with the ambient light modulator, similar to what you and Denis are doing in this thread. I think your technique could be built upon to create a more realistic inverse square falloff at each point. Nearby clouds won't have proper shadow-casting or self-shadowing this way, but you probably don't need that very often.
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Overall, it's just not an appropriate method or look, where clouds are.
Yeah, that's true at short ranges. Voxel cache-based GI doesn't give you a sharp inverse square falloff close to the stars, whereas you could do this with a glow function.
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I understand you want to declare [glowing clouds] a method that isn't appropriate due to how things function, but for final results, it's the only method appropriate besides manual light source placement.
I think I understand what you're trying to do now. Until recently you were using tiny points of light much smaller than a pixel, so I thought you were just trying to create something for the GI engine to pick up on (hence my trying to show you that rocks do exactly the same job - and I promise you they do). But if you guys are using the glow to simulate the light falloff around the star, then I completely understand and I think you have a good idea.
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I haven't played with GI much, I did with my first stars and literally no adjustments fixed seams, but those stars were absolutely tiny, and not 10+ meters from 1000m scales.
Yeah, it doesn't work well.
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A populator would be amazing. And for still work, which frankly, most people do in TG, it's amazing. Though as shone with my offset example, the stars positions remain true even at a offset of 5000m.
Additionally, you can use this method for global volumetric clouds, an actual cloud layer above your planet. Similar to using the background object but actually luminous and positions vary based on your position on the planet (though in the real world these variations would be much smaller. Probably obtainable with super huge scales or a very thin depth to prevent "depth".
Yeah there are some advantages related to how you position the stars that might be more cumbersome with a populator.
BTW, the background sphere can be made luminous - just throwing that out there in case you didn't know, and I see a lot of people mapping images onto the background without knowing how to make it luminous. You just need a Default Shader and plug into the luminosity function or the luminosity image.
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The second example looks promising. But, unfortunately, the methodology just doesn't translate well. It still creates pixelation out of the clouds, and playing with GI on a per-project basis was always a turn off for me.
Yeah.
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The stars themselves do not look good, and are not varied in size appropriately, leading one to insert many populations masked for appropriate procedural stars, as well as many more for depth. I see you used the terrain node to create some depth but this doesn't seem to be working well?
I didn't spend any time trying to make them look good, but with a few minutes work their density, brightness and colour could all be modulated using fractals and lots of other interesting ways.
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Especially for a cloud depth of 20000m. Rock populations at this point would be adding 10x the work, in place of something that seems to be working despite the debate. Couple of the stars literally inside the nebula seem to do no close range glowing, it's all one solid carpet of luminosity at it's max distance on the the upper most drop-off.
Yeah, it lacks proper fall off at close ranges. At long ranges it should be correct.
Matt