Hi,
I thought I'd make a new post regarding this, since the last I've seen are from 2011 and 2020.
Is there a reason why Arnold doesn't have a Voronoi shader/texture node?
It's definitely one of the main noise required for many different setups.
Or is there a way to create one, custom plugin etc. ?
Something similar to the texture from Blender.
all the best,
amwilkins
Hi Thiago,
Thank you...yeah I've seen that one.
But does it produce the same results when used for something like a normal map?
Just some quick testing doesn't appear to, but maybe I'm doing something wrong.
We just get black and white values?
Result I'm hoping to see. Better faceting.
Thank you!
amwilkins
You need to invert the cell_noise. Once you do that it works:
cell_noise
{
name mycell
pattern noise1
additive 0
amplitude .5
scale 5 5 5
coord_space "object"
lacunarity 5
}
subtract
{
name invert
input1 1 1 1
input2 mycell
}
bump2d
{
name bump2d1
bump_map invert
bump_height 0.05
}Thank you Thiago, that's interesting it's needs to be inverted and also have to use Noise1 or Noise2.
Surprised the Cell Noise doesn't appear to work with the same setup.
Another question, again trying to match some behavior to Blender here and show there is some interest in more features on these nodes if required.
How would you smooth the sharp edges in Arnold?
Thanks!
amwilkins
Very interesting thread! The noise being used here is not Voronoi noise but rather inverted Worley noise. So instead of creating bubbles, it creates dents. Voronoi noise would be the cel noise. The reason cel noise does not work as a height map is that it gives back flat cel values rather than ranges. However, for this cartoon look you kind of want that. The idea is to flatten the normals with the cels. An approach that I found worked for this:
1) celnoise "out" into "in" of randomColor this gives random colors in the cels.
2) The random colors are in the range ([0, 1]) for (R, G, B) channels. Normal directions range from ([-1, 1]), so the random values need to be remapped.
To do this multiply by 2 then subtract 1
3) Normals must be unit vectors (length = 1).
You can do this with a normalize vector.
4) You then combine this with the world space normals using a lerp. The world space normals you can get in Arnold with a state vector set to N. Then blend that with an aiRange for Arnold or in materialX you can use a mix. The mix value of 0.8 worked pretty good for me.
5) The final result goes into the geo normal input of the surface shader.
We've an incredible amount of noises coming with rtoa 1.6 😋
Voronoi with edge smoothing for example.
🤘
