NUKE NUGGETS Weekly

- [Steve] Hi this is Steve Wright welcoming you to this week's Nuke Nugget, how to create a wound reveal animation mask. In the grisly world of visual effects we're often called upon to animate the reveal of an ugly wound. Here we'll see a very effective technique for creating a convincing animated mask for a wound reveal. So, this is the effect we're going for here. We're always having to reveal the wound. Notice this gets thicker over time and it has this wonderful from center out, it grows out like this and has all this fine, fiddly little detail.

Well, we get this from a mask that looks like this. So, we're going to be seeing how to create and animate this mask. Okay, so starting up over here, the overall workflow is we start with a very simple shape that looks like this drawn with a rotor node and then we add a fall off in the brightness from center to edge, that's part of the key for revealing it from center out, a bit of a blur just to smooth things along, then a grayed node here that will actually do the reveal animation like so.

We're going to go through all this in detail, just giving you the big picture here. Then this just hardens it up til we got a nice solid core everywhere and this mask is then taken in for distortion. Okay? So, let's take it from the top, zoom in and see what we got. So, from up here we home this, come up and open up the rotor node. So, this is really very simple. The idea is that these rotors on the first frame are shaped to be rather thin and then on the last frame they're thick, so you have just two frames very, very simple.

So, it looks like that. K, so this gets us the thickness variation over the length of the shot but this does not get us the reveal from center out to edge. That comes next from this radial node here. K, so we take this radial node and we multiply it times this rotor mask and that gets us this. We're trying to get a fall off in brightness from center to edge.

Now, we follow that with a bit of a blur and this blur is animated and take a look at what we got here. On the first frame when we are as small as we possibly can be, this is the thin frame if you will, and then we get thicker over the length of the shard of course, so while it's thin I gave it a pretty good blur of eight and then at the other end, a blur of five, so you'll have to dial that in based on, you know, the thickness, and size and shape of what you're trying to do but that's the idea.

Okay, that just kind of softens the edge and blends things around nicely. Okay. Next, and here's where the reveal comes from, this grayed node here is animating the black point. So, starting on frame one, the black point is set to suck the whole thing away, okay? The reason it works is because of this fall off here in the luminants, k? So, this grayed node is now pulling it in, cutting it down, over the length of the shot like this, so we'll start like this at the beginning and end up like this at the end.

So, we put that animation back and then I'll just play that for you here. And there we go. Now, you'll notice that, let me get to the last frame here, it does what I want but the brightness, look at my brightness values as I roll from center to edge. You see? It's falling off, falling off, falling off, so we want this to be solid, so this next grayed node here pulls the whites up, all I did was a gain of 10, no animation, and don't forget very important turn on your white clamp, okay? Otherwise this thing is going to blow out to very high values and you don't want that.

So, now watch my code values as I cruise from center to edge, I'm a solid 1.0 everywhere until I get to the very tips and then it starts to fade off but that's fine, that'll add to the organic reality of the whole thing. Okay, so that gets us the basic animated mask and all we got to do now is get our distortions into it, the deformations. Okay, so that happens down here. We start with this noise pattern here. Let me re-home my viewer.

So, the idea is we dial in the X, Y size until we get the look we want. Now, it's linked to a second noise pattern here. This noise pattern is linked for the X, Y size, so they move together but the first one has a different Z value than the second one. There you go. K? The reason we have two of them is one will be deforming in X and the other deforms in Y.

You don't want to use the same noise pattern for the deformation in X and Y, it doesn't look quite right. So, two different noise patterns but they're locked together in size, so as we adjust the size of the one, it will affect the other. So, we put that guy back to where he was. So, just used a copy node to move the red channel from one into forward V and on this one I used the same red channel into forward U. So, now the forward U and V have two different noise patterns.

We can see that here, while I say show me my forward, so the red channel has forward V and the green channel has forward U. Alright, okay, back to RGBA. Alright, we then pipe that into an I distort node. Just dial up the amount of I distort, you know, you can turn it down if you want less distortion and now we are ready to rock and roll. And there we go. So, there you have it.

How to create a wound reveal animation mask. Be sure to check in next week so you don't miss out on my next Nuke Nugget.