Cineversity

I’m not sure if this is a glitch, but I’m trying to understand what is going wrong in this scene, I have two snt tags, set up in a heirarchy. I’ve set blending mode to multiply, but when I render, the “AO” tag glitches out the strokes created by the parent null tag, making a mess of glitchy black bits..
My intention is that the strokes will multiply over each other.
There’s quite a few settings, so I’ve uploaded the scene file;
https://www.dropbox.com/s/r2moifar8pz6nbx/sketchnToon_test2.c4d?dl=0

you’ll see if you disable one tag, the other displays perfectly..

In case my render differs, here is a screenshot to compare:
https://dl.dropboxusercontent.com/u/24304389/sntLineGlitch.jpg

Hi NNenov,

Yes there are many parameters, and after each adjustment you should do a little test render, or have the Interactive Render Region open (opt/alt + R). So you will see what influences what, anything else will blur your learning experience.
As you wrote there are hundreds of parameter, and while learning, it is not a good idea to do more than one step and without checking what happen. Yes, I know, sometimes problems show up later. Hence the Auto save should be enabled to compare different states.

I’m not certain if Material Hierarchies are at all suggested nor if one should avoid those. I would avoid them. It seems more appropriate to add them to one object directly.

If you use Multiply for example, the top Material should be set to it, not the lower part. It might not matter in most cases, but to have a clean set up doesn’t hurt.

File
https://www.amazon.com/clouddrive/share/MTWajUWa1NbbNWVWdofzJZ9jtkHE3xOHNvnRYxWVajp?ref_=cd_ph_share_link_copy
Screen-Shot
https://www.amazon.com/clouddrive/share/Yz119bJSSW5XosIzY8cIoNz1Uy3L9ierqZkvYWA2HW4?ref_=cd_ph_share_link_copy

Set the black material now to Blend: Multiplied to see the difference.

Screen-Shot
https://www.amazon.com/clouddrive/share/K1xzi22CWhF0EGv3mDtDO3uqbOrX6ouxw9BwM77NkhR?ref_=cd_ph_share_link_copy
Not that clean, a composite would be nicer.

I tried also to multiply the transparent over the opaque, which results in new problems. But just to be a little bit more complete:
https://www.amazon.com/clouddrive/share/HpfepQrpMnXMri6b0cal0D0m65z1blijXOnD7FNhF2X?ref_=cd_ph_share_link_copy

If nothing works to your liking: My suggestion, render the black lines with a white Shading/Background and mix it later in post.

To get clear what is working or not, the first step would be to enable or switch each material. IF this isn’t helping, create a new material and replace it within the Tag. One by one. Leave this material on default.
Materials in SnT have a Priority (Main Channel), that might or might not help, based on the set up.

Problems will always occur while experimenting, so exclude parts, compare, exclude the others. Etc. RMC to get the manual what some parameters do is certainly advised. Otherwise some conclusions might stuck and limit your development.

All the best

Post is updated Sun:03:03pm PCT

Thanks for having a look, I am a bit confused now, both of your files/screenshots yield the same artefacts I was getting.
I’ve tried setting up the most basic scene possible;
Whenever I use more than one SnT tag, where the first tag is black, full opacity;
The second tag will cause the *aliased over-spill* glitch if:
It has opacity any lower than 100%,
It has colour lighter than perfect black, set to any blending mode.

Surely this is a serious issue, but I’m sure I’ve seen sketch n toon renders with overlapping strokes before..
Is there not even the most basic example scene showing two strokes blending/overlapping in a normal working fashion?

I have contacted support, and I also understand I can do separate renders/takes and composite in post, but I want to understand why I can’t get any non-broken results using opacity or blending modes, if the options are there they must have been tested / intended to function properly..

I think the issue here may have something to do with the order the strokes are created, and the position they are drawn.
To me it looks like when there are two snt tags, when strokes overlap, they interfere with eachother, another term for this I think is called Z-Fighting.
You can see very simillar artefacts occuring when you have two snt tags, both with opacity set to 100% and blending mode to normal, like it doesn’t know what order to render them in, they get all messed up..

Hi NNenov,

The screenshots shared doesn’t show the same problems as yours.

Which suggests at this point to consult the support.

https://www.maxon.net/en-us/support/how-can-we-help/

My best wishes.

Hi Dr Sassi,

Your screenshots don’t show the same artefacts as mine, but if you look closely you will see the strokes become thicker and aliased, which is happening in my project as well, but in my example it looks a lot more messy because I have noise/distortion on my stroke.
I have been in contact with Maxon and they weren’t able to immediately resolve the issue, it has been forwarded to the dev team.
For now I am going to have to render separate takes and comp them, more effort but at least I get the added control over each style render this way.

Thanks for going to the Support,

I hope they find a solution for you.

Multiplications with perhaps zero values, so far I can see based mainly on the Noise and strong transparence settings, are my main suspect, besides a set up that I wouldn’t suggest: Hierarchically.

You can use the Take System, then it is only loading all in a stack (e.g., Ps, or Ae in a comp) and set the blend modes. Tahnks to the take system that is quiet comfortable.

Until they find something, compositing is certainly the best idea.

My best wishes.

Here’s an interesting development; I posted about this on reddit, and someone with c4d r16 could render this and with distortion with almost no artefacts whatsoever, seems this may be an r17/18 issue?
link to the post:
https://www.reddit.com/r/Cinema4D/comments/5wh2g1/help_with_sketch_toon_overlapping_strokes/

S/he had a great idea, which you can see here with a R12 rendering.

Thanks for the reminder that this wasn’t in our discussion so far. I get better results in R12 when I switch off Curve Stroke. (It is more visible when the Back ground is rendered to black and the strokes are not black of course, in the screen-shot I use your colors and Curve Stroke is active)

Here is the screen-shot
https://www.amazon.com/clouddrive/share/6gwE7vuonvxYu2xR1Pfhn4nfdFDa58aN2m51rfHs4Mj?ref_=cd_ph_share_link_copy

Well, this explains the confusion so far

However, setting the colors to blue unveils other problems. Here is a rendering along your settings of R12
https://www.amazon.com/clouddrive/share/v0KKRHqDhBXiFNFeg8LX4zVkToxvyGb1Xlq4bbj1WE0?ref_=cd_ph_share_link_copy

All the best

Edit

One more try,

This is done in R17, and I only changed the Attribute Manager> Render> Self Blend and Blend. Please check this.

Please have a look

File https://www.amazon.com/clouddrive/share/GdgkhAzQdeQaQRK7ltrSP7RsSaMbeWGsg8SkFJfl0SX?ref_=cd_ph_share_link_copy

and the resulting jpg (but rendered in 32bit/channel/float)
https://www.amazon.com/clouddrive/share/qM51tlcK6C0pooFMV9oMXxCWT8hP5OhegyZEZm18Do?ref_=cd_ph_share_link_copy

It is a little bit fuzzy where the background “stroke” is more opaque than elsewhere, but that happens even if set to Normal.

All the best

How about setting the black line to “Folds” as well:

https://www.amazon.com/clouddrive/share/nIXym0eCL7BiMMmd2URAYiXUhxtt6wxafAorSBLdEhm?ref_=cd_ph_share_link_copy

Screen-Shot
https://www.amazon.com/clouddrive/share/DAA8RFELVRwG4IZ8RLQNvsuJP0TZVHpeWxNnPHr0ESk?ref_=cd_ph_share_link_copy

The SnT tag could be set as in your initial file (Not my suggestion—as before—same result, tested and shown here in R17 as you mentioned that you use this.

BTW, if not mentioned otherwise, I assume that the current version and update is in use.

The Support/Dev team should have the next word on it.

Cheers

Thanks for the keeping at this, I did a render from r17 of the newest file you sent “NNenov_sketchnToon_test2_Fold-both.c4d” zoomed in section:
https://www.dropbox.com/s/j35dsw4snfhmj0q/overlaps.jpg?dl=0

Its definitely an improvement!
I’ve set up all my takes now and in a way its a better way to approach this, but definitely not if you are in a hurry!

Thanks for the visual feedback, NNenov, I see exactly the same.
You might have notice that the Compositing in Ps will be clean.

All the best