Sparkle

[dandelO]

Something I left rendering over Christmas night.

I was trying for the sparkly effect that was mentioned in this thread... http://forums.planetside.co.uk/index.php?topic=8350.0
By using fractal specular functions.

2x Walli's Grass patches. 1x TG grass clump.

Not perfect but still something I'm working on. (I'm not at home so I don't have any postwork tools here, no usual sig', either, these are just raw TG-outs)

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Thanks for looking!

p.s. Some other tester images will follow in the replies...

[dandelO]

Test 1...

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[dandelO]

Test 2...

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[Tangled-Universe]

Interesting approach using the specular function input of the default shader (at least, I think).
On the first image it looks really good, almost there, just a bit brighter
On the 2 test images I'd say that the scales should be reduced a bit.

However, the big problem with this in general is clearly shown in test 2 on the far right. In TG2 you just can't get specular's all over your image beside giving it a huge spread and increased strength, but that looks ugly.
I think if you really want to achieve the result you're after you can try to use the fractal function as luminosity and play with that. Or like me, use tiny luminous fake stones, but that's also not that easy.

I really would like your thoughts on this and what you thought about it so far

Cheers,
Martin

[dandelO]

What I think might be an idea, Martin, is to use your fake stones idea and add fractal specularity to them.

Nice, there'd be no overall reflection-spread because the spec' would only appear where stones were. A high IOR on little, sparse stones might be good, I'll try...
I'm not keen on using luminosity for this, although, the image I posted first in this thread uses some but in a different way. The pinkish hue of the snow is added to with faint pink luminosity, it isn't just the atmospheric effect creating the colour there.

Off to play...

[Tangled-Universe]

Why a high IOR? Does that "force" specular reflection?
If you still use specularity to achieve the effect you still have problems with having specularity only "under" the sun (image-wise).
Unless a high IOR results in specular reflections with less amount of light needed?

[dandelO]

The way I understood it, a high IOR creates more reflection, I want to capture spots of sunlight on only specific areas, where the small stones describe it. Adjusting specular roughness is a way to make the specularity sharper/rougher but I wanted to make them really 'glint' by reflecting the sunlight. I'm still playing...

[domdib]

Interesting experiments - just wanted to say I LOVE the clouds in the first one.

[Tangled-Universe]

The way I understood it, a high IOR creates more reflection, I want to capture spots of sunlight on only specific areas, where the small stones describe it. Adjusting specular roughness is a way to make the specularity sharper/rougher but I wanted to make them really 'glint' by reflecting the sunlight. I'm still playing...

That's where our goals differ a bit. I strongly don't want to have specularity only where my sun directly lits the terrain. I want it almost everywhere, very gently, like you see in many photographs.
Difficult difficult difficult.

But, you showed me carrot

[dandelO]

Another test, I'm having trouble with AA bloom, though. It appears too strong, giving a plastic look to sparkly areas, disabling it gives unwanted black reflection outlines...

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The sparkle is very apparent and, the way I see it, the glint from the snow in life is refracted sunlight through water crystals of the snow. If they're recieving direct light rays, they'll reflect/refract and give a glint according to your POV. It will be all over the surface but only show up where light will shine through it. Reflected light should also be creating rays to light up areas out of direct sunlight.
This is a tricky problem but we usually figure things out here when we all chip-in with different ideas.

This image uses your tiny fake stones idea(they're 0.00025m scale/0.025 spacing), no tallness or pancake effect so, they're simply spots, all over the surface of the snow layer.
Rather than using specular functions like I did before, these have a completely flat, zero scale, transparent water shader as their surface shader.

EDIT: Stone coverage is too high, this is making it too reflective and plasticy, the bloom is working beautifully with a lesser sparkle coverage(0.0025).

WIP...

[Tangled-Universe]

With high GI settings, but probably at insane settings, you should also get sparkles in shadowy areas. At least that's something you see in images on the net.
I'll try to post some links to show what I'm after.

I think you need more roughness to pick up more specularity by the way.

[Thelby]

I don't know how you will do it TG2, but I think the effect you are after is simular to 'Sub-Surface Scattering' in Vue. Is there any type of way for anything like that in TG2???

[Dune]

This is probably more what you're after... don't mind the landscape, that was just plain out of the box. Some snow added and the sparkles.

---Dune

[Tangled-Universe]

This is probably more what you're after... don't mind the landscape, that was just plain out of the box. Some snow added and the sparkles.

---Dune

Ah yes...almost there, say 90%!
It would be nice if there are some more sparkles, smaller and a tad less bright.
Did you do this using the reflection function + specular roughness function or just plain clever specular settings?

[Hannes]

Yes, that's pretty close. I agree that the sparkles should be a little bit smaller, but imho they should not be less bright.