How can I get a mask from tile sampler?

dimwalker · Oct 2021

Using few tile samplers for leaves.

First of all. is there a way to get a mask from sampler? I can crank up levels on sampler result to get a mask, but it will "grow" and have nasty rough edges. Solution I'm sticking with at the moment is leveling each leaf and then using copied sampler with those leveled leaves plugged in to have exact same pattern/distribution in mask.
Though, this approach has its drawbacks - each time I change something in original sampler, I have to copy it and replug all those leveled leaves again. Which is already inconvenient and will get even more annoying since I want to use 3 different samplers mixed together with height_blend. So I would have to juggle 6 samplers in total(3 for main pattern and 3 for corresponding masks).

What would be a best way to go around this? Is there any "native" solution to get a mask from sampler? Or maybe I can wire 2 samplers together with some scripting/function voodoo magic?

Image: https://i.gyazo.com/999d88a056a587f928af2960dad8884c.png

gnoop · Oct 2021

Usually people use shape splatter nowdays . It has a companion data extract node for this.

If for some reason you don't want to use shape splatter. It has very limited scale range on narrow textures 256x2048 for example . So sometimes sampler is a better choice.

In such case you can use a trick of giving your inputs some hidden gradient and ID through sort of frequency separation and use two of such gradients to get UV that you can use to remap color info or masks .

here is an example of such gradient:

Image: https://us.v-cdn.net/5021068/uploads/editor/ux/4zd44gf14gsr.jpg

You have to "fix" the tile sampler node first to make it working in 32 bit math although. For some uncertain reason it doesn't in default one. And the trick is working only in 32 bit mode.

You would have to do it 2 times for UV and one extra time for input objects ID indexes. So 4 tile samplers working in sync. Shape splatter would work quicker probably.

I

dimwalker · Oct 2021

gnoop said:

Usually people use shape splatter nowdays . It has a companion data extract node for this.

Splatter's shape height affected by its size confuses me, but I guess it's kinda like tile sampler's size-amount dependency I will have to get used to.
Anyways, shape splatter looks promising. Thank you.

dimwalker · Oct 2021

...
You have to "fix" the tile sampler node first
...

Wow... that was quite an edit, mate

I'm afraid your wisdom is lost on me. Fixing node's math, multiplying by extra white - this graph looks like it's written in alien language.
Could you share fixed sampler please? I guess there is no harm in using better one even if I don't understand all the benefits. Though, if possible, would prefer it as additional node instead of replacing old one.

gnoop · Oct 2021

Actually you could just make a clone of your tile sampler and make it work with inputs alphas in 8 bit mode. No need to remap anything. Sorry for over -complicating.

Also you can use FXAA node to "fix" " nasty edges".

That "hiden gradient" UV idea still might be useful if you want to use the leaves color counterparts instated of recoloring scattered result.

The idea is basically making your thing(hemisphere) super high like skyscraper and add a subtle roof gradient on the top , so subtle it's make no essential difference . Like a carrier wave and a signal. Then after you scatter the thing you subtract your skyscraper ( without gradient) and get only the gradient itself , now rotated and height {Max} blended properly. Do so with another gradient, rotated 90deg and you get UVcoordinates you can use to map color counterpart of same sphere/input picture on.

As of fixing tile sampler to work in 32bit mode set fx-map inside to absolute/ 32 mode and add any node after pattern input that also set to absolute/ 32 bit output .

poopipe · Oct 2021

Use the colour version of tile sampler . Alpha is passed through from input to output

gnoop · Oct 2021

yeah. poopipe is right . those UV gradients or even splatter node are necessary only if you want to use Max (lighter) blending in between scattered things to get kind of proper height blend . ( like in the initial screen)

But for leaves it could be just regular alpha blend since they are mostly flat things and laying one over another naturally .

if you want to pass the height through "alpha blend " kind of scattering it's more complex thing to make it look real. I usually just do it in layers . Kind of series of tile samplers each doing sparsely scattered, non-overlaying things in certain height range and use the first one as a mask input for a next sampler and so on. And it doesnt grant you always right appearance anyway.

Would be nice to have a scatterer that would prevent things intersecting each other like in some 3d soft. Usually a human eye instantly and subconsciously catch such intersections and get an unreal impression. Something working like UV packers maybe .

I never managed to do it .. Our programmer wrote a script that can but I couldn't even figure out how it works.

dimwalker · Oct 2021

@gnoop
Small intersections are alright. I'm trying to do my work as well as I can within reasonable time. In this case perfection is not needed since it is a racing game and tree won't be on player's screen for too long.
Afaik speedtree is used for serous foliage and can distribute leaves respecting collision, but I never used it.

poopipe · Oct 2021

speedtree either makes leaves - in which case they aren't going to intersect - or uses the textures you give it - in which case it's your problem.

if you want to make decent foliage you have to grow it - there's pretty much nothing you can do in a 2d context that will prevent the occasional weird intersection short of modelling the tree in 3d and baking a texture out of it. This isn't that nobody's written a tool yet - you simply can't.

As Gnoop says we usually get around it for things like hedges etc. by layering sparsely distributed color tile samplers / shape splatters (whatever it's called) it's generally "good enough" but under close inspection it falls down .

Within the substance designer ecosystem it would be very complicated to build a scatter system that fully respected 3d intersections etc. I don't think fx-map based distribution would work unless the system were extended but I think it's theoretically possible within a pixel processor -I'm doubtful about how practical it would be at resolutions you'd actually want to work with though.

Now i've written that down somewhere public we just have to wait a couple of months,NicholasW will implement it and we'll see it in designer shortly after

How can I get a mask from tile sampler?

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