Film visual effects for crying?

[akent99]

Not sure if this is the right place to ask, but for creating videos / movies / cartoons / linear content emotions is often important. Smiling, talking, etc can be done with blendshapes and bones on faces etc. There is lighting for mood and shadows. But is there a good solution for tears and crying?

There are different strengths of crying of course (tears welling up in eyes, tears from corner of eye, weeping, hysterical crying, tears dripping from face - as well as sweat on face (Anime style) etc). And challenges for tears to follow the eyes (e.g. blinking while tears welling up in eyes, then running down the face, then gathering up on chin, then dropping to the ground).

Example with tears at bottom of eyes (should track with eye opening and closing), on cheek, extending from chin (so cannot just be a texture trick?), forming drips etc. I cannot even think of the right technology for this. I am doing crude stuff with textures at the moment, but moving to HDRP it feels like I should up the quality to be consistent.

[mgear]

(random thoughts)

at least for rain drops there’s shaders like
https://github.com/yumayanagisawa/Unity-Raindrops
and other meta blob effects…

but i’d guess could be easier to control results by drawing/pre-rendering them (outside unity),
although if its 2D sprite sheet / animated decal something, not sure how that looks over 3d object - when viewed from any angle…

[akent99]

@mgear

at least for rain drops there’s shaders like
https://github.com/yumayanagisawa/Unity-Raindrops
and other meta blob effects…

Yes, shaders might be the best answer. (Note: For film if it looks good, it is good! Who cares how “clean” or complete a solution it is.)

https://twitter.com/Sakura_Rabbiter/status/1531213809612107776?s=20&t=BKeyLf0V1_ko47_1tdqGVw is also a pretty good example of what is possible with a “skin shader” for wet skin. Maybe shaders can do things like water dripping from chin…? Or maybe too hard and stick to shaders.

[ellka]

I asked to artists internally, got this answer:

A rain shader similar to this would probably work for streaming tears:

Raindrops Shader Graph - Unity URP Tutorial + Photoshop texture tutorial

Or maybe if you want something more tangible you could probably sim water/tears in another DCC and bake out the animation to an Alembic file?

You could probably use a looping blendshape on a tear line mesh to get the water overflowing the eyelids effect Id imagine.

[akent99]

Thanks Erika,

I have tried some other rain shaders, but gave the one you shared a go as well. The others were not shader graphs. (I need rain on glass for another scene as well, so its useful regardless.) If I understand, I cannot “stack” shaders - so I have to work out how I can add the above to the RealToon cel shader I am using. I tried as an experiment creating a transparent sphere around the head for the tears to go on - but you can see the sphere even with sphere smoothness set to zero. (I was going to duplicate the face mesh to be more accurate, but he looks like an astronaut! Or a goldfish…)

So right now the best approach seems to be a shader, but it needs to be merged into the skin shader somehow.

I also need to draw better rain drops!

[merpheus]

I believe the best way to do such a thing would be painting flow maps on character and adding vfx drops on top of it for actual drops. From what I recall TLOU2 uses flow maps for things like this. Also for rain drops on skin etc.