Ice Cream - Shader progression 1/1/10 - page 2...

[dandelO]

A different method for sparkly snow using luminosity blended by a tiny fractal with huge negative colour offset to leave just spots, instead of the specular attempt I made a few days ago. This is similar to my night background node for stars but on the ground instead.

The falling snow in the distance is horrible, I think. I should have left that out.

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Thanks for looking!

[Tangled-Universe]

Very nice result! Great!
To the far bottom left you see a group of fainter sparkles. This is the brightness I'm looking for. Your brightest sparkles are a tad too bright imo.
Now you only need a little bit more sparkles and you can choose to blend them out in the distance, I think that's more realistic.
Fantastic!

Martin

[Henry Blewer]

Definitely on the right track.

[dandelO]

Cheers. The luminosity value was 4 for the glinting, maybe about 2 would be better if it looks too bright.

Here's a shot of it...
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The 'sparkles' surface layer(on the left) has 'apply colour' unchecked, it just provides luminosity on the basis of the 'sparkle function'(its blending shader).
The tiny scales of the function fractal are colour offset to -1.1, leaving just spots where the brightest points are.

Blending by distance would be good, yes.

* The speckling in the distant hills is actually failed cloud shader snowfall, not the snow surface layer.

[Tangled-Universe]

Thanks for sharing this. I'm working on another approach as well and will share my findings too.
I don't think all your sparkles are too bright, only the brightest, therefore besides the settings you've shared already I'd like to know the contrast and roughness settings of the blending fractal. This greatly affects how that luminosity will be applied and should offer you the possibility to get sparkles with the same brightness or at least not so much variation.
I'd choose for high contrast and very low roughness and then either use the luminosity function or high color of the fractal to control the brightness of the sparkles. See what I mean?

[Zairyn Arsyn]

Cheers. The luminosity value was 4 for the glinting, maybe about 2 would be better if it looks too bright.

Here's a shot of it...
[attachimg=#]

The 'sparkles' surface layer(on the left) has 'apply colour' unchecked, it just provides luminosity on the basis of the 'sparkle function'(its blending shader).
The tiny scales of the function fractal are colour offset to -1.1, leaving just spots where the brightest points are.

Blending by distance would be good, yes.

* The speckling in the distant hills is actually failed cloud shader snowfall, not the snow surface layer.

i will have to mess with something like this later on once my current render is done.

[Dune]

Don't you get the problem with this method that the bright sparkles also turn up in shadowed areas? I'd like to see a render with more shadow, and indeed without the falling snow. I'm testing something at this moment, but I use a tiny fake stones layer+ reflective shader (+ a small scale blender with a - color offset).

By the way, I like your billowy snow.

---Dune

[dandelO]

I'd choose for high contrast and very low roughness and then either use the luminosity function or high color of the fractal to control the brightness of the sparkles. See what I mean?

Yes, Martin, I have tried with many different variations in fractal colour settings. The contrast here is 1, while the roughness is default 5. This ensures that the spots of the blending are nice and bright when offset is dropped. Regardless of this fact, colour roughness has no effect here - all scales of the fractal are the same, there is nothing to roughen. Contrast and offset is fine for controlling brightness, in this instance. I need a more constant method than a power fractal, I think, a one-octave perlin noise function input would be better controlled, easier to have a constant map of spots of more equal brightness, maybe even just some colour adjust shader levels to the fractal output before it feeds the luminosity shader.

The balance between offset/luminosity has very little margin for error, raising offset also brightens the spots and so makes the following luminosity brighter, you then need to rethink how bright that needs to be, it's very incremental.

Don't you get the problem with this method that the bright sparkles also turn up in shadowed areas?

I do indeed, Ulco, and it somewhat annoys me when I see it rendered. It has, however, been snowing here repetitively since about a week before Christmas and I have been observing real sparkles in the shadows aswell. Clearly not as bright or abundant as if in straight light but light can still be reflected from other sources.
It's trying to make it look convincing enough to believe when real life tells you otherwise.

I'd still love a TG way to keep them out of the shadows, though!

Cheers, folks!

[Dune]

I might have something, as explained in another topic (cannot recall which one, ah.. the one about the shadow function). Have to try it again today. Last chance this year!

[dandelO]

The 'sparkles' surface layer on the left has 'apply color' unchecked, it  will provides luminosity on the basis of the sparkles function. Thank you for sharing this information with us.

Yes, that's right, David. And this is also true for many other parameters in shaders, they don't all have to supply colour information to the node chain, even if they are listed as 'colour shaders'.

I'm now in the process of honing this shader. I'm using a perlin 3D scalar node in place of a power fractal now, it's far better suited to this task - one scale, colour adjusted to create a more even sparkle map. Everything can be controlled from the mother shader's parameters - snow colour/sparkle brightness/snow displacement/slope/alt' constraints etc. This will eventually be another single surface layer that can be easy dropped into scenes to cover your terrain with convincing snow and blended however you like with any other shader.

I have also restricted the sparkles by camera distance going from an eye-level POV(about '2m v,Y'), as discussed above. This can be easily adjusted by visiting the distance shader parameters if you need a higher POV, the distance shader is hidden and used as blend shader for the, also hidden, 'sparkle' nodes.
It'll be a simple setup, easy to use for any user.

I'm, at the moment, tackling some intersect underlying options so that close-up displacement is more convincing than it is now.

Pending...

[dandelO]

A new preview with intersection rules applied for the snow-piling is rendering.

I think my slope constraints need a little less fuzzy-zone softness still. I'll post shortly...

[dandelO]

There are still a few glaring problems. My fuzzy-zone softness, I think, needs to be tighter than '1', and the fractal displacement is kind of shady, too.
I also will raise the slope constraints, this is just to see how it reacts to slope. These constraints are '45' and fuzzy '5'.

The sparkle cut-off is at a decent level for a true scaled, eye-level POV. The scales/roughness of the snow shader displacement needs tuning. It's too full of fractal lines. I think I'm going to take this to the function level, aswell, to get more control over the surface displacement. I really don't like the fractal displacement.

All these settings are default for the snow surface layer; Colour = off-white/blue, Luminosity(or, sparkle function) = '1', displacement = '1'. You'll be able to pile snow upon terrain/displacements to any height. This is a POV of = 2m v'Y', or, roughly eye level, in real world scale.

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Stay tuned for better snow detail, I plan on really tuning this some more, I really do hate this fractal displacement...

[Mandrake]

Very nice dandelO, you definitely achieved that sparkle affect! I like the first one best.
Looks like a great addition to your next pak!

[Henry Blewer]

I usually cover these with a population or fake stones (the edges of the fractal). I have not figured out how to 'smooth' them yet.

[TheBlackHole]

Try adding more octaves. That or a little more displacement with a smaller scale and smaller displacement. It worked in my "Rocky Hills" image (remember the first one? that had some fractal lines), so why not try it here?