topic Re: Voronoi texture/shader for Arnold in Arnold General Rendering Forum

Voronoi texture/shader for Arnold

am_wilkins — Thu, 11 Apr 2024 07:15:04 GMT

Hi,

I thought I'd make a new post regarding this, since the last I've seen are from 2011 and 2020.

https://forums.autodesk.com/t5/maya-ideas/voronoi-noise-node-and-blender-like-shader-controls/idi-p/9779886

https://forums.autodesk.com/t5/maya-shading-lighting-and/voronoi-cellular-noise-patterns-in-maya/td-p/4186190

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

Re: Voronoi texture/shader for Arnold

thiago.ize — Thu, 11 Apr 2024 23:28:04 GMT

https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_user_guide_ac_texture_shaders_ac_texture_cellnoise_html has voronoi noise.

Re: Voronoi texture/shader for Arnold

am_wilkins — Fri, 12 Apr 2024 07:41:45 GMT

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

Re: Voronoi texture/shader for Arnold

thiago.ize — Fri, 19 Apr 2024 21:28:12 GMT

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 }

Re: Voronoi texture/shader for Arnold

am_wilkins — Tue, 23 Apr 2024 09:10:05 GMT

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

Re: Voronoi texture/shader for Arnold

martinkindl83 — Fri, 03 May 2024 03:48:45 GMT

thats awesome to know,

years ago, when the new cell noise came out, i was told by developers, those two noise type wont work with normal/bump in general, something in code.

Glad i found its working, even though 4years later 🙂

Re: Voronoi texture/shader for Arnold

am_wilkins — Wed, 15 May 2024 08:21:08 GMT

Hi @thiago.ize

Just so we don't leave this thread hanging, is smoothing the voronoi / cell noise result possible with Arnold?

(like the "Smooth F1" mode in the Blender example above)

Would be great to get some confirmations and if not possible, to perhaps place a request for this feature.

All the best,

amwilkins

Re: Voronoi texture/shader for Arnold

thiago.ize — Thu, 16 May 2024 01:03:50 GMT

Sorry, I have not tried creating a shader network to do this. I assume it should be possible maybe through clever use of ramps or clamps? Building all of this into a shader that ships with Arnold would of course be nice.

Re: Voronoi texture/shader for Arnold

am_wilkins — Thu, 16 May 2024 08:52:15 GMT

Ok, thanks for the update!

Let me know if you get a chance, I've built some pretty cool looking stuff in Blender using this technique and would love to do the same in Arnold/port it over.

"Building all of this into a shader that ships with Arnold would of course be nice."

100% gets my vote, for what it's worth.

amwilkins

Re: Voronoi texture/shader for Arnold

stella_ng24GWZ — Wed, 12 Jun 2024 04:33:03 GMT

Hi,
I've been playing around and trying to do some testing with blender set up in maya and found that aiRange is a good node to use to control the fall off of aiCellNoise.

Re: Voronoi texture/shader for Arnold

am_wilkins — Tue, 18 Jun 2024 10:31:36 GMT

Cool!

Unfortunately, still doesn't smooth the edges of the voronoi pattern.

Re: Voronoi texture/shader for Arnold

dflood — Mon, 14 Apr 2025 16:41:54 GMT

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.

Re: Voronoi texture/shader for Arnold

maxtarpini — Thu, 17 Apr 2025 21:58:37 GMT

We've an incredible amount of noises coming with rtoa 1.6 😋

Voronoi with edge smoothing for example.

🤘

Re: Voronoi texture/shader for Arnold

2689081964 — Sat, 17 May 2025 05:18:19 GMT

Yes, maybe it can be used, but it is charged.
I mean, yes, you developed this, and your charge is understandable.
But we have already paid for arnold. Should they be provided to us for such general functions? Instead of asking us to buy other plug-ins to supplement arnold's ontology? This is very unreasonable.

Re: Voronoi texture/shader for Arnold

maxtarpini — Tue, 15 Jul 2025 20:12:36 GMT

Those talking like you, never spent a dime on software in their whole life.

Shut up, take the shader and get lost.

https://www.rombo.tools/downloads/romboNoiseCellularSmooth.zip

Re: Voronoi texture/shader for Arnold

2689081964 — Sat, 19 Jul 2025 05:29:07 GMT

No, I don't think there is anything wrong with my statement.
I think I made it very clear that you have developed this plug-in, so it is not a problem for you to charge, which is completely reasonable.
I'm talking about the routine functions like this. We paid for arnold, but arnold didn't provide them, which is a bit unreasonable.
Let me give you an example. It's like you bought a car, and then they told you that the wheels and steering wheel need to be bought separately. Yes, if I really need to buy the wheels and steering wheel, it's reasonable for us to pay for it. However, it's reasonable to say that I bought a car, and the wheels and steering wheel should be attached to it.
For example, you buy a mobile phone, and then they tell you that the battery and charging cable need to be purchased separately. Battery and charging cable are the basic accessories for the normal use of this mobile phone, shouldn't they be included? As a result, they want you to buy them separately.
If your mobile phone is a modular mobile phone, and then you want to enhance your camera lens on the basis of the original function of the mobile phone, then a company has developed this extra lens, so it is reasonable for us to pay for it, and no one will say anything.

Re: Voronoi texture/shader for Arnold

daniel — Sun, 20 Jul 2025 08:06:01 GMT

@2689081964

are you dense? A simple thank you, very appreciated is all to reply here. Please stop cluttering this forum with your nonsense.