I've just tried what you said and in fact the unified noise doesn't even
seem to use the full [0, 1] range as one would expect from reading the doc.
At least not in H13. Or maybe I did something wrong. If this turns out to
be true, it'd kill the primary purpose of the node to bring coherency
between the different noise types. Not great for lookdev as you said.
This bring back blurry memories where I digged into the unified noise a
couple of years ago and ended up coding my own, maybe because of this exact
reason. But then I eventually lost the digital asset that I had built and
ended up using the default noises instead :)
On 27 April 2017 at 16:42, Andy Nicholas <a...@andynicholas.com> wrote:
> The `Unified Noise VOP`, which is a fairly useful node that outputs all
> the noise values in the [0, 1] range, takes pretty much all of its logic
> from the `pyro_noise.h` include file. Which means that you can easily have
> access to the same functionalities in VEX, like so:
>
> #include <pyro_noise.h>
> v@perlin = vnwrap_perlin3(v@P, 0, 0);
> f@pflow = fnwrap_pflow1(v@P, {1, 2, 3}, 0);
>
>
>
> Aah, thanks for that Chris. Didn't realise you could access the noise
> functions like that. Good to know :)
>
> Also, it's interesting to see how they managed to unify the noise values
> in `pyro_noise.h`: they basically ran a lot of samples and picked the
> min/max values of each noise to approximate their range. Statistics for the
> win! :)
>
>
> Yep, that's what I've been doing. I'm concentrating on FBM modes of
> evaluating the basic noise functions (noise(), xnoise(), snoise(),
> onoise(), anoise) as that's what I tend to use the most. Unified Noise is
> okay, but I still find problems with shifting offsets in the noise.
>
> For example, make a grid with 150 divisions, create a Unified Noise in a
> Point VOP and set it to use Signature:->"3D Input, 3D noise", Noise
> Type->"Perlin", Fractal Type "Standard (fBm)" add the vector output to the
> point position and then try playing around with the Max Octaves,
> Lacunarity, and Roughness. You'll see that you get a global uniform "DC"
> offset along the each axis. That's not cool! If I'm using that as a noise
> force, then it has just pushed all my particles in the (1,1,1) direction.
> You'll also find that switching between noise types noticably changes the
> amplitude range. Again, not great if I'm doing lookdev and I just want to
> try a different noise type without changing the general magnitude force
> amount.
>
> In addition to sampling the noise values, I'm doing some curve fitting to
> that data in Python's scipy which smooths out some of the statistical
> glitches with the sampling. It's giving some good results that don't
> exhibit the DC offset that I mentioned above. All this should let me create
> a replacement for the Anti-Aliased Noise VOP. I'm not dealing with the
> anti-aliasing aspect yet though, so it won't be as good for shaders, but
> the offset isn't quite so important in that context as it is for using it
> for forces.
>
> Still need to do some testing and then package them up into VOPs, but once
> they're ready I'll release them in siLib for everyone to try.
>
> A
>
>
>
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--
Christopher Crouzet
*https://christophercrouzet.com* <https://christophercrouzet.com>
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