Underwater Caustic Effects with Perlin Noise

[Cardin]

Underwater Caustics

Effects animator Adam Phillips demonstrated how to achieve underwater caustic effects using Toon Boom Harmony. That software has an effect module called Turbulent Noise but this is the same as Perlin Noise which is already available in TVPaint. One demo in particular was a rather nice effect so I wanted to see if I can replicate it using our preferred software, TVP, with procedural generation.

Adam Phillips' demo of the effect I attempted to do can be seen at about the 15:08 mark [IN THE SPOILER]

Spoiler : :

And here is what I was able to do with TVPaint and animated procedural textures using Perlin Noise. I "animated" the additional elements (fish[stroke animator], bubbles[particle generator], and hammerhead shark shadow[static image transform over optical flow field]) but they're not meshing too well. My goal was to achieve something similar to Adam Phillips demo. With some more tweaking I believe a much more realistic result can be achieved. To that end, more water and refraction study must be done.


The gif is approx. 13mb so it might take a few moments for smooth playback.....



Feedback would be appreciated.

[ematecki]

That's the most creative use of Perlin's noise I have ever seen !

[Benjamin Cerbai]

Really nice ! I will share it on TVPaint social media so other users can learn about your work and the way you achieve that kind of effects.

[Animationriver]

We are all waiting for a cool video lesson on how to make these effects))

[Cardin]

Thank you all!

I knew it could be done when I saw it in the manual - https://www.tvpaint.com/doc/tvp11/index ... sma-perlin. There are so many possibilities with Perlin Noise!

@AnimationRiver - I'll try to put something together. I don't have a webcam or quality mic but maybe just a video showing the steps would suffice. BTW, I have been following your tutorials for a while and find them very helpful. I only know one language, English, but I am able to get the gist of most of them

[Animationriver]

@AnimationRiver - I'll try to put something together. I don't have a webcam or quality mic but maybe just a video showing the steps would suffice. BTW, I have been following your tutorials for a while and find them very helpful. I only know one language, English, but I am able to get the gist of most of them
[/quote]

Hello! Thanks for the kind words.
I think you do not need a web camera and do not need a microphone. You need a program to record activity on the screen. Leave the essence of steps without sound. And it will be very useful for all of us. )) Your results attract everyone. And even those who love the comfort of viewing and those who only look at the essence.
But, it makes sense, if you want it.
  Thank you!

[D.T. Nethery]

I knew it could be done when I saw it in the manual - https://www.tvpaint.com/doc/tvp11/index ... sma-perlin. There are so many possibilities with Perlin Noise!

The underwater effects you made using the Perlin Noise FX look good . I too would be interested in seeing the process to arrive at these results.

Honestly, I have never paid much attention to the Perlin Noise FX , because I didn't really understand what it is intended to be used for. Now seeing your test sent me back to the user manual and back to the FX Stack to have a closer look. It's an interesting effect. I tried a simple application of it to get a gentle rippling effect on the surface of a calm sea . I still don't understand how to control it very well , I just eyeballed it , trial & error , until I got something that sort of achieved the effect I wanted , but there is still much to learn !

https://www.youtube.com/watch?v=v3UTfBfcK9Q

[o0Ampy0o]

Underwater Caustics...
Feedback would be appreciated.

I don't mean to be disrespectful or to suggest this is anything but beautiful. But just to provide feedback based on my impression of the result here, there is something about the pattern that reads more like surface waves than you would perceive if this were merely lighting on the bottom of the body of water. Not sure of what it is exactly except that it is probably taking place at the transition edge between the light pattern and the unlighted area of the floor color. I will have to study it further when I have more time.

When I first viewed this upon accepting my initial impression I anticipated that we were above the surface of the water. I did not pay attention to bubbles of other indicators. My eye was attracted to the light pattern. So, based on that I perceived it as the water surface. It was not until I took in other factors that I realized what it was intended to be. At this point if I had to point to a source I would say the transition should be more abrupt.

I think the shadow needs to be more distorted by the light pattern as well. It reads more like it is the actual fish. And I know this was a quick experiment but the fish is not swimming or gliding from momentum through the current or from thrust conforming to its body shape and fins.

Again, this is gorgeous and inspiring. I am happy to see that something like this is possible in TVPaint. I only am providing requested feedback which might help you perfect it.

Look forward to seeing more of this effect.

[Cardin]

Underwater Caustics...
Feedback would be appreciated.

I only am providing requested feedback which might help you perfect it.

Constructive criticism is what I was seeking and that's exactly what you provided Thank you for clear and concise comments, Amp! There are time when things can look "good" yet be very inaccurate. I'll certainly use your honest feedback to improve upon this test since after review, I tend to agree with your critique. I think, perhaps, instead of trying to mirror Mr Phillips' test, I could have done more study of actual underwater refraction on the seabed.

I tried a simple application of it to get a gentle rippling effect on the surface of a calm sea . I still don't understand how to control it very well , I just eyeballed it , trial & error , until I got something that sort of achieved the effect I wanted , but there is still much to learn !

Whoa now that looks good to me, D.T. Nethery! I was hoping someone would join in the fun . I thought a slightly different method might be necessary for the surface but I think you achieved a convincing effect. Thanks for sharing it. I'm inspired to try something on the surface. As you stated, there is much to learn and I hope we can all gain from each other's tests. So please post more tests if you are so inclined.

I'll post a video of the process I used in the last test soon.

[o0Ampy0o]

While eating dinner I took another look at this. I compared the final work with that of Adam Phillips's and noticed three things that might help to consider when doing the bottom surface as well as when aiming for the top surface.

I think this first one holds true to a sort of rule of cartoon world animation. Of course you can define your own universe but this applies to the more general cartoon world scenario. Unless there is a context which defines a reason for an exception the viewer's perspective needs to conform to general rules of our reality. In this specific case, the angle of view for the bottom of the ocean typically is elevated more and looks down. Unless you are supposed to be a bottom feeding life form you would not usually see the bottom of the ocean as though you were standing on it. This is one difference between your experiment and Adam Phillips's sample. His looks at the bottom from a higher perspective. When aiming for the water surface you would either see from the perspective as an occupant on a boat (for example) or you would be up high in the air. There would need to be a reason provided by the context of the story for an angle other than these two general areas.

The second factor that I suspect is contributing to the illusion that this is a water surface rather than light refraction on the bottom of the body of water is the degree of contrast. Your darks are darker. This creates the illusion that the pattern is occurring on a surface of waves rather than a flatter seabed. The higher contrast makes it seem as though the shapes are bending the form creating shadows that conform to a mass. In principle, one is the effect of pure light while the other is undulating mass. Light in this context does not cause form to change shape. Only the light changes shape.

Now this will probably trigger the thought of refraction. Even though refraction is distorting the form its effect is more like a color overlay except it is a perception overlay. In both cases the solid object remains stable. It is the ability to see the solid object's "local color" and "local form" (could that be a term for it?) that is being effected by the color overlay of a mass of transparent water or the perception overlay of this mass of water also undulating so it bends and breaks up what we see through it.

The third is the light pattern's movement perspective. It is going to be influenced by the angle of view. Less vertical (forward to back / back to forward) and more horizontal widening and narrowing. If this has an adjuster in the software whatever equates to left / right would move at a different pace than front / back. It appears to me that this is equally balanced in your experiment.

[Cardin]

While eating dinner I took another look at this. I compared the final work with that of Adam Phillips's and noticed three things that might help to consider when doing the bottom surface as well as when aiming for the top surface....

Excellent points. ALL of them.

Thank you, Ampy. I appreciate you taking time out of your night to provide a thorough analysis. You convey a sense of understanding about the subject so every point in your critique will be useful when I revisit the effect. Your comments on the perspective, color, and movement are very helpful and I definitely welcome that same critical eye on future tests.

Here's a quick overview of the steps I used for the first test. It would have taken too long to build an entire scene so I just did a quick demo of one way to start the process. I hope its useful to someone. My apologies for the low quality.




With inspiration from D.T. Nethery's test and Ampy's helpful comments, I was motivated to attempt an above surface shot. In this test I drew a beach scene and played around with the perlin noise parameters a bit. Then I used another perlin noise mask layer as the source for Displacement Mapping on the Beach/Rocks texture from the Papers Panel.

[Animationriver]

Cool Stuff!!!

It's amazing!
Maybe you have an idea how to make waves of the tide?

THANKS!!!

[Cardin]

Cool Stuff!!!

It's amazing!
Maybe you have an idea how to make waves of the tide?

Thanks!

Tides and waves...
No, but that's one of the reasons why I wanted to start engaging the community more, to learn ways to improve my character animation and fx. My knowledge of how to apply perlin noise doesn't extend too far beyond what I demonstrated in the video and that's not even scratching the surface of what can be done. Seeing D.T. Nethery's test led me to try something different so hopefully that will continue. I would love to see more of that from anyone willing to share.

[D.T. Nethery]

Cool Stuff!!!

It's amazing!
Maybe you have an idea how to make waves of the tide?

Thanks!

Tides and waves...
No, but that's one of the reasons why I wanted to start engaging the community more, to learn ways to improve my character animation and fx. My knowledge of how to apply perlin noise doesn't extend too far beyond what I demonstrated in the video and that's not even scratching the surface of what can be done. Seeing D.T. Nethery's test led me to try something different so hopefully that will continue. I would love to see more of that from anyone willing to share.

Going back to this discussion and your tutorial on using Perlin Noise for water effects , I'm wondering if you or anyone else here
has used it for recreating the classic "ripple glass" effect to show objects as underwater ,  such as seen in Pinocchio or Fantasia ?





(the Perlin Noise could be used for the patterns on the ocean floor in the Pinocchio clip , but I'm trying to figure out how to get the turbulence/rippling effect over the entire scene , so there is subtle distortion. )

It's been so long since I tried playing around with the perlin noise FX that I have to relearn it (your tutorial is helpful:  https://youtu.be/wQHMEgbZDrw )
What I'm trying to get is a displacement or turbulence over the characters and background that would show the "rippling" currents ,but not actually show a pattern superimposed over the character and background , just the subtle distortion of the rippling.

I'm trying to get something like the effect shown in this video -  https://youtu.be/2LXeqtxEaQ8?t=262
using an effect in Premiere called 'Turbulent Displacement' .   I could just do it as shown in Premiere , but would prefer to keep everything in TVPaint if possible rather than take it to Premiere or After Effects (I'm sure AE has a similar Turbulence effect).

.

[Svengali]

David,
You might get something like what you want from the OpticalFlowDeform FX.
sven