I’ve always been curious to learn more about how these types of VFX are done. I would guess fluid sims with some mesh particle chunks…and are the the fluid sims baked onto a sprite sheet or is this some real-time stuff being rendered? Would love to find out from any VFX artist that has done something similar!
@Partikel knows this stuff way better than me, but the technique I’m used to is eroding a mesh particle using vertex colors. Creating a blood splat mesh with some carefully deliberate vertex painting as a mask, you can shrink and hide parts over it’s lifetime.
This is similar. No alpha erosion though. It’s using fluid meshes in a sequence, so essentially this is playing a few baked fluid animations. When framestepping, alpha erosion has some obvious tells. This one has changing shapes instead of just reducing ones. I’m counting 10 frames on the most unobscured one. There are several of these sequences mixed in.
Very nice effect!
Thanks for the replies, Partikel and Chris! Going to do some research on the methods mentioned and see if I can replicate the feel.
anyone know of a good houdini tutorial for making fluids like this?
Come see my GDC talk 
The lighting on it is beautiful, really fits the environment well.
Is it at this year’s GDC?
There was a Naughty Dog write up on the fluids they used in The Last of Us that they might be using on the sprites. It went over baking a fluid sim and layered each frame on top of one another in the alpha channel, so when they eroded the texture it smoothly stepped through the shape of the long stringy fluid breaking apart. I can’t remember off the top of my head how they handled the normal map/normals. It may have been the same technique for the red and green channels combined together in the shader/material.
The Naughty dog thecnique is using thresholdmaps. They handled normals by making a normalmap and then modifying it by the “height”. I tend to ignore that step and simply sample the “heightfield” and generate the normalmap on the fly.
I don’t think the Res effect uses that though, as thresholdmaps while cool are still only a sprite so it won’t get lit like that. Thresholdmaps often suffer from wonky edges as well as thresholding an alphamap can only give so much.
The above effect is one of two things. Either it’s meshbased, or it’s prelit sprites made specifically for that lightingsetup (or with a few lightdirections baked in)
@Eben held the awesome thresholdmap presentation. It can be seen here: GDC Vault - Surface Tension: Liquid Effects in The Last of Us
I’ll be sitting in the front row, schedule permitting 
I just meant some of the background sprites might be using it, not the ones you had highlighted in that gif. I should have clarified that with my first reply
Yeah, could be. So much stuff going on so it’s hard to see 
I’m not sure how you’d determine whether it was prerendered models or just a limited physics step. The smoke textures are in sync to my eye, but i could be wrong. We could just be seeing their framerate?
I see some bits disappearing abruptly which would make me think cached meshes.
I’ve seen nvidia flex do very similar things, but not so much that i’d call it on a bet.
I can’t be 100% sure of course, but all examples I’ve seen of flex has that supersmoothed meshing since the particle sim is so lowres. These ones are lumpy, like the would be if you meshed a reasonably highres sim.
Here’s kindof what I mean. The resident evil thing has the lumpy stringy thing going on like this:
While flex tend to give smoothed out results like this:
(Hard to illustrate without flex though…)
Do you have any examples of games using flex I could have a look at?
To me they just look like a fluid sim with normals, alpha, and maybe AO, baked out into a few flip books. I can’t speak to which fluid sim they’re using though.
Could be. But then they were extremely lucky with the lightingdirection in this gif making it match the environment perfectly or they have a better way of handling normals than I’ve seen before.
RE was released in VR aswell wasn’t it? It would make sense for them to move away from sprites where possible.
I’ve been doing normal mapped particles for over a decade now. Done right they’re indistinguishable from meshes in most situations, at least for opaque objects, so I’m a little confused by your comment.
As for VR, while it’s true it’s a VR game I’ve noticed most of the AAA devs doing VR work still stick to the “traditional” VFX methods. Part of that is the PS4 is in no way powerful enough to do those effects as meshes and keep 60hz, so traditional sprites are often your only choice.
It is really easy to spot sprite effects in VR, but people usually don’t seem to mind or care. One of my biggest peeves with billboard based particles in VR is if you roll your head to the sides and particles will “stick” to your face. I fixed most cases of this in Wayward Sky (in part by using mesh based particles, but not always), and in a proprietary engine I contracted on for a bit, though that project is no more.
But, again, most people don’t notice because for most games you don’t spend a lot of time “rotating” your head like that, and you rarely have effects lasting long enough.
I’d love to see some examples of normalmapped sprites that look this good! I’m not saying you are wrong. I’m saying I haven’t seen any normalmapped particles that look this well lit. If you could point me to where they are, I’d love to study them. I’m curious since the only way I’ve gotten results like the RE one is by using meshes. I never could get normalmaps to look good…
I found another clip of the same effect. Check it out in 0.25 speed: https://www.youtube.com/watch?v=6fhDR8iOonQ&feature=youtu.be&t=238
Here are some key frames where you can see the paralax of the mesh.
