Daydreaming on shadow catcher

Started by uuderzo, July 14, 2020, 08:36:32 am

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Dune

So you're playing with the method I mentioned? Shifting the mask for stones for snow pile-up? You may need a voronoi setup to get a really rounded, more uniform base. I tried perlin, but the pile-ups didn't always match. I also tried using fake stones masked by the base mask, but they are too inconsistent. It is pretty hard to get soft, smooth snow and rough stones.

WAS

Yeah that's what I've initially been using after showing how FS will still be angular and useless really.

I am using voronoi billows which works alright. Kinda down to seed cause still some bunching here and there that kinda does the perlin blob thing.

This does work nicely I must say, but it lacks any melt areas and breakup to intersections without full PT subsurface, but unfortunately shadows are broken up and hard.

I may put this up on my gumroad tomorrow for donation optional (their free mode thing) if I dont go into emergency dentist.

WAS

July 18, 2020, 02:14:47 pm #32 Last Edit: July 18, 2020, 10:08:23 pm by WAS
Another issue with using billows, is the voronoi folds can end up on your buildup, and no way to remove them. Similar issues when creating lateral displacement with voronoi, I'm sure you're aware.

Idea

It would be cool if there was a function for the world light source position (based on whatever input sun), that could be used in conjunction with the dot product of the terrain and normals to do what we want via sun position. Now shadows needed, just position of a sun.

uuderzo

Tried a variation on @Hetzen and @WAS hints.

This time i placed the rocks on a planet, and the drifted snow on a second planet (both planets are identical and simply work a "domain separators").
I find the result quite promising, there is some little glitch where surfaces are nealy matching but this is mainly because i didn't work on a plane. By the way, not working on a plane adds some interesting variations on the drifts, ok they are not wanted but they are there, maybe using a different shifting method may fix this :D
Shadows are ok (i added some translucency only for aesthetical purpose, just to see the result but looks like it works also without SSS).

Dune

The hard edges in the snow drift is what was my problem too. If time permits, it would be interesting to have a go at a good way to do this.... I have an idea in my head (remembering an accidental shift once), but hope to be able to find it again.

uuderzo

Would it be possible to compute the gap between the two layers and use it to drive the shader transparency?

WAS

Looks good, how are you smoothing the fake stones?

The best way to handle the transmission is going to be the glass shader and longer render times using pseudo subsurface or PT, but with PT shadows break.

But yeah when I use Fake Stones the angles are just too much (see attachment)

uuderzo

@WAS, to smooth fake stones i routed them to a heightmap generator, then smoothed the heightmap and shaded again on another planet, identical to the first one. I attached the project to my previous message.
The problem would be using the same technique with a rock population...

WAS

Oh that's a great idea. Didn't even think of that.

And yeah, a rock population would be difficult. I think the microexporter can handle rocks on terrain with proper settings if I remember from tests. That could be used in another program to smooth up and give than imported as a plane and offsetted.

Also I uploaded my projects: https://planetside.co.uk/forums/index.php/topic,28102.0.html

WAS

Quote from: uuderzo on July 19, 2020, 02:17:34 pmThe problem would be using the same technique with a rock population...

Tackling that, there seems to be no way to make sure the population lands on exactly every spot in your map, but for the most part, rocks do show up where they need to be.

I used a very high contrast unclamped billows map, plotted where rock pops will go, than used a plane/planet with a colour adjust and smooth maximum clamp to make those small tight spots larger and smoother, than smooth maximum for a smooth transition to snow. Some voronoi creases in this example but changing seeds you may end up without them. Or you could feed the displacement shader to a height field and use the smooth filter like you do with fake stones.

You could just call the mounds without a rock being smaller rocks encompassed in snow.

Kadri

Does have anyone tried the classic erosion plugin (maybe the procedural could work too)?

WAS

Quote from: Kadri on July 19, 2020, 11:45:54 pmDoes have anyone tried the classic erosion plugin (maybe the procedural could work too)?

I was going to but the smooth on heightmap will work for all. However, I think with some smooth clamping of different layers and using thermal you could actually create a aged buildup where some had melted and more built up.

uuderzo

Quote from: Kadri on July 19, 2020, 11:45:54 pmDoes have anyone tried the classic erosion plugin (maybe the procedural could work too)?
While i like your solution, please allow me to ask you to elaborate on how you used the null shader. Current TG documentation on it is really poor and i cannot guess how did you make it route to the planet for rendering.

uuderzo

Quote from: WAS on July 19, 2020, 02:39:43 pmOh that's a great idea. Didn't even think of that.

And yeah, a rock population would be difficult. I think the microexporter can handle rocks on terrain with proper settings if I remember from tests. That could be used in another program to smooth up and give than imported as a plane and offsetted.

Also I uploaded my projects: https://planetside.co.uk/forums/index.php/topic,28102.0.html
Sorry I messed up the threads and answered in the other one  ::)

Dune

I think I got something for you guys. Will upload later...