Need Help With C4d Material Nodes

[adploshko]

Hi,

I've been getting into C4D node materials recently and I'm surprised there isn't much info on what each node does in the official documentation. I've watched the entire material nodes playlist on Cineversity, but that only covers some of the nodes. Is there a comprehensive list somewhere that elaborates on what each node does?

Also, I've been experimenting with making NPR shaders using nodes, and I want to try and make a cel-shader that also interacts with global illumination. I've been able to achieve this in standard materials using Sketch & Toon tags or a mixture of Colorize and Lumas shaders, but not with Node materials.

The closest result I could get was recreating a basic cel-shader from this video: https://www.youtube.com/watch?v=8BdHQK8URWI

However, it only responds to the intensity of light objects, not the global illumination or light color. So I'd like to know, is there a way to replicate the function of a Lumas shader in the material nodes?

Any advice on these topics would be greatly appreciated.

Thanks

[noseman]

@emotion-police

...I'd like to know, is there a way to replicate the function of a Lumas shader in the material nodes?

The Lumas shader is Light Based and NOT GI based. It will only react to actual light objects.
Unfortunately, the New Nodes won't support dragging Objects (including Lights) and using their position to create an equivalent to the Lumas Shader.
Your alternative is to use the old Shader Graph (XPRESSO Nodes) and create a material with Only Emission, and drive that emission using a few nodes:

1. Drag any lights in your Graph and get their Global Position.
2. Using a State Node, get the Normal output (the direction of the normal at every rendered pixel) and do a "Dot Product" with the Light's Global Position.
   The dot product of 2 Vectors (normal and Light Position) define the "Perpendicularity" of the two vectors. So if the Normal is pointing towards the light, the product is higher (brighter), while when facing away, it's darker. The result of a Dot Product is just a plain number and NOT a vector.
3. Using a "Change Range" you can define the smoothness of the falloff.

In the attached scene I have used 2 lights and I'm using a Color Layer to mix the result of the 2 calculations by controlling the Mask for each color. The Layer color defines the color of the light.
Although not perfect, it may get you closer to your goal.

https://www.dropbox.com/s/zj5ng9rnp2vvg4w/Lumas%20equivalent%2001A.c4d?dl=0

[Dr. Sassi]

Hi adploshko,

I'm not sure if it is advisable to spend a lot of time in the Default/standard node system.

Take at look at the OSL shaders:
https://github.com/redshift3d/RedshiftOSLShaders
If you scroll down, you will find light-object responsive ideas. As Noseman pointed out, the old ways of using the Light frustum or coordinated even, doesn't cut it anymore, with the many sources, like IBL, GI or Caustics even
OSL is more of a developer questions, but I would not know who in which developer forum would support learning this.

Please keep an eye on RS-Trello for that
https://trello.com/b/QASr74yB/redshift

Perhaps have a look here, at 22:00 [min:sec] NPR
https://on-demand.gputechconf.com/siggraph/2018/video/sig1844-robert-slater-final-frame-rendering-gpu.html

Please post your needs here:
https://www.maxon.net/en/support-center
"Share Your Ideas"

I will keep this in mind and update the thread when new options arrive.

My best wishes

[adploshko]

@Dr-Sassi @noseman
Hi,
I initially explored the OSL route with Redshift, but I ultimately gave up on it as it seemed to me that making a custom NPR shader that responds to all ray types and GI would require making a custom closure in Redshift's API, which is not public. Hence, I settled with the pre-established Sketch & Toon module instead.

In the material nodes, I notice there are Ray and Trace Ray nodes which have a GI output. What can these nodes be used for?

Also, back to the main inquiry, where can I find a comprehensive list of each node's function? As stated before, I can't find any info in the official documentation and the Cineversity playlist on the topic only demonstrates a select handful of the nodes.

[Dr. Sassi]

Hi adploshko,

You will find both Nodes that you asked for here: Not compatible with Redshift 3D)
https://help.maxon.net/c4d/2023/en-us/Default.htm#html/NET_MAXON_PATTERN_NODE_GENERATOR_RAY-NET_MAXON_NODE_BASE_GROUP_OUTPUTS.html?TocPath=Node%2520Editor%257CIndividual%2520Assets%257CMaterial%2520Generator%257CTrace%2520Ray%257C_____4
and here
https://help.maxon.net/c4d/2023/en-us/Default.htm#html/NET_MAXON_PATTERN_NODE_UTILITY_RAYINFO.html?Highlight=ray

There is no extra documentation other than what is provided as official Documentation.

My personal take:
As mentioned, I would not spend much time in this Standard Render Node system. But I try to get some of its functionality into the RS system.

Perhaps write a request here: "Share Your Ideas!"
https://www.maxon.net/en/support-center

Even the XPresso-based Redshift 3D Node system has a comment in the Documentation to be aware that it will have no future.

If you learn a node system, focus on the Cinema 4D Redshift 3D system. I try to keep the new system on my screen and don't spend any time (if possible) on anything else.

Perhaps this one will help you already
https://help.maxon.net/r3d/cinema/en-us/Default.htm#html/State.html?TocPath=Shaders%257CUtility%2520Shaders%257C_____15

All the best

[adploshko]

@Dr-Sassi
Hi, when it comes to Redshift, I always use the default shader graph which looks like the Xpresso one. Are you saying that this system will be removed entirely from C4D/Redshift?

Also, regarding the C4D material nodes (not Redshift), is there no way to manipulate GI lighting to achieve NPR effects (e.g. with the aforementioned Ray and Trace Ray nodes)?

[Dr. Sassi]

Hi adploshko,

Please have a look here:
https://help.maxon.net/c4d/2023/en-us/Default.htm#REDSHIFT/html/Redshift+Material+Tools.html?TocPath=Material%2520Manager%257C_____2
The second red framed text. I have attached an image.

I quote here only. It is not my opinion, nor do I spoil here any secrets; it is since a while in the manual; Obviously, it is not read.

NPR is not a defined look. The term is based on excluding something that is also not defined. Or why do we, as Cinematographers, argue about Film vs. Digital?

I know it might be splitting hairs, but asking for NPR is so general that I can't provide an answer here. Redshift is, going public announcements for quite a while, creating a new NPR system. If it were just a few nodes tossed into a Node editor, it would be released by now, IMHO.

Here are two examples to get information from the Cinema 4D default Node system.

CV4_2023_drs_23_NOcd_01.c4d
CV4_2023_drs_23_NOcd_11.c4d

This is certainly NPR.

Enjoy your weekend