Masks and Track Mattes
We now want to go and talk about track mattes and masks, because I want to combine this superhero scene into the cloud. And this is really kind of the climax of everything that we've done so far. Like we want to have Stu imagining that he is something greater and we haven't been able to do that, so we want to put all of this scene with Stu and the media and the fire, we're gonna put all of this in his thought bubble. How do we do that? We do that with something called a track matte. So I'm gonna put this over the bubble, and then here's the key, here's what I need to do. I'm gonna take the superhero scene, the composition that we had, drag it below the main thought bubble so it's underneath, and then in this modes column right here, and by the way if it's not showing you'll have a Toggle Switches and Modes button at the bottom. You can click it and then swap from this which is called the switches area, to the modes. And if you're seeing both then you don't have that button and it's fin...
e. You can also alternatively, and again across this bar you can right click, choose columns, and then choose to see modes, but you need to see the modes. So the superhero scene, this None drop down under the track matte, we want to choose Alpha Matte. So what this is going to do, it's going to have the superhero scene use the transparency information of the layer above it. That's the alpha, alpha means transparency. Matte means mask. So it's using the layer above it, the cloud, as a transparency mask. It's gonna tell the superhero scene where to be. So I'm gonna choose Alpha matte, boom, and now we have something really beautiful. This superhero scene is using the thought bubble as a transparency mask. So now we have Stu finally after a whole day of After Effects training we finally have Stu reading a book and seeing himself as a superhero. So really kind of poetic in a sense. Also it's kind of not that poetic though. So let's talk about masks. We talk about mattes and check mattes, and by the way, I should also point out that track mattes are not limited to just precompose layer. Any layers can do things that they want. Leah has a question?
When you nest those within another composition, if you go back and you make changes to that will it change it in this composition that you've nested it into?
Yes. Yes. Very good question. So question is, if we change it and the child composition will it ripple through, and the answer is yes. So let's say I want to dig all the way down to the original meteor. And I'll boom boom, boom boom, and here's the meteor. And let's say I want to make it darker, and I can do that by just really, super, super fast I'm gonna apply hue saturation, it's a really stupid way to do this, don't do this but just for very fast, and I'm gonna take down the lightness so now we have kind of this dark volcanic lava rock instead, then when I just go back, I don't have to do anything, I just go back to the library scene and now we have a dark rock. So yeah, as we drill down, the changes all ripple up on the top. So you can, it's a little confusing but you can go into the project panel and duplicate the composition so that it's not the same thing, it doesn't have the same source if you want a different version of that, but that's how that works. Thank you for the question. Okay, let's talk about masks a little bit. I'm gonna close up precomp meteor, and I'm actually done with the superhero scene and the library scene, so I want to talk about masks here. I have this text Read Go Anywhere, that's like our theme for the day. And I want to create a background, and throughout the day you've been seeing me with this kind of multi-gradient background, and I've created that with masks and that's what we're gonna talk about right now, I think masks are tremendously helpful in motion graphics and visual effects, anything you use After Effects in, masking is really helpful, so we're gonna get a couple quick uses of masks. What I want to do now is I want to turn off the visibility of my text and I'm going to right click in this little spot right here, I'm gonna make a new solid. And I'm gonna click the color. I'm gonna pick a nice bluish kind of color. Kind of create something very similar to what we've been working with. It doesn't seem that loud when I'm picking the color. So I'm gonna right click, actually no I'm gonna select it, go to the layer menu, solid settings. I'm just gonna make it a little bit more green. I'll put darker, desaturated. There we go, okay. Now. This is a plain color, it's fine, it's great, but with a little bit of extra pizazz we can make it feel a lot more sexy. So I'm going to make another solid. And this one I'm gonna make a little more green and a little brighter. But just as layers do this layer completely replaces the content underneath. So I just kind of want a really subtle shade of this green that I just made in the center. So what I can do is go to my tools that we used to build shape layers, but because I have this layer selected now they're gonna create masks. So I can click and drag and make a mask because I have that layer selected, and now the layer only shows up inside of that mask. So I'm gonna undo that really quick. So what I'm not gonna do is instead of clicking and dragging I actually want this to be full frame, I want this elliptical mask to be full frame, so I make sure my solid's selected, and I'm just gonna double click this, and this is another one of those secret codes that's awesome. I double click this and this mask shows up in the center. And now what I want to do is come down to my layer and there's masks and mask properties so I'm gonna open up mask one, and here are the four mask properties. And what I want to do is actually reduce mask expansion to bring that in. And I can also increase it, expand it, but I just want to bring it in because I want this in the center, and then I'm going to increase mask feather oh so much. A lot, a lot, a lot, a lot. And now it just dissipates it, it just feathers the mask, and now instead of having this really rough edge we have this really elegant spot of light. It's almost like you have the most gentle, loving spotlight in the world just right there on the center with a different color, and the gradations are so soft and subtle, it's just really, really beautiful. Now, another thing that can do. Select a solid and I'm gonna duplicate this layer. Command D on the Mac, Control D on the PC to duplicate this layer. And now I want to darken the edges. So I need to change my color by going to Layer, sorry I always use the keyboard shortcut, I always forget where it's at, I use Command Shift Y. So Layer, solid settings, and now I'm gonna go back to more of a blue but I'm gonna make it a little bit deeper and richer, a little darker. Again we're kind of creating a little vignette here. But right now it's still in the center and it's kind of replacing the stuff in the center, so I'm gonna change something called the mask mode, I'm gonna type M, to reveal the basic mask property which has this drop down, and by default masks will add the content. In other words they will only show up inside of the mask. But I want to do the opposite because that's what we did with the center where that showed up only inside of our mask. I actually want to cut a hole with this one so I'm gonna change this from add to subtract, and now the dark stuff is on the outside. Now when I close that mask, open it up, and mask expansion I'm going to increase this so in the same way we use mask expansion to bring in the mask, we're now using it to expand out the mask. So now if I turn this off you can see the difference that makes, maybe we want to push it out a little bit more. There you go. And so now we have a pretty elegant background. Pretty easily, pretty quick, but it's much better than just one solid flat color. So now I'm going to select all these layers. I'm gonna select one and I'm gonna Shift Click. Select all of them and drag this beneath my text so that I can see my text when I turn back on its visibility, which is pretty cool. Okay, so what I want to do is I'm gonna make a new solid. This is a really common trick for motion graphics, and before shape layers this is all you had, but even with shape layers sometimes this is a cool jam. So what I'm gonna do is I'm gonna right click. New, solid, and I'm gonna make this one black. And what I can do here is use the rectangle tool with the black solid selected. I can click and drag and make kind of like a mask. Now that's way too bold for this design. I'm just gonna drag this underneath. We can read the Go Anywhere text because we want to drag this underneath, and now this text shows up and we can see the mask. Now when I go back to my mask here and I'm gonna go back to my selection tool and move this mask where I want it, and masks are really great for creating little graphic elements like this. And so what I want to do is I want this bar to sync up with my text. So when it finishes coming on like right there, I want that to be a keyframe, so I'm gonna open up my masks value and I'm gonna set a keyframe for mask path, because the mask path I want it to have this shape and be in this location at this frame. And so now I'm gonna back up and then when it stops right there that's when I will, and I'm just gonna double click the edge of the mask so I get this bounding box and I'm just gonna drag this over here. Click okay. And sometimes you might get a little sliver of black that can be annoying like that, so what I'm going to do is I'm gonna trim this layer, I'm gonna click and drag this intro point here and drag that in so it just doesn't start until this point. Now I can back it up. And we have this kind of cool little motion graphicky thing. There are a couple moments where it kind of looks like the text overlaps the mask, so I might want to adjust the mask keyframe if we drag it in a little bit closer. Yeah. And if we had time I'd change the colors and we'd change the speed of this whole thing and there's a few things we can do that are unrelated to masks and track mattes that we could do to polish this up, but pretty cool to be able to do this with the power of masks. So you can animate masks to be different shapes, do whatever. Masks are great at revealing things, it's potent. Just another quick example, I'm gonna select the left lighting. If I wanted to make this lighting kind of look like it's striking, one of the cheesy things you can do just in a pinch is you could take a mask and reveal the lighting. And same way we did with the black bar, the black solid, it's the same thing but just kind of a different way to get you thinking about different things you can do with masks. So I could create a rectangle, click and drag on the lighting. I mean you could do this in several ways, but what I'm gonna do is subtract this so everything in the mask doesn't show up. And then I'm going to set a keyframe for mask path. Move in time. And then resize this so this scales down. So then over time, this lighting bolt kind of comes crashing down, and we can make that a little bit faster so no one can see the wizard behind the curtain. Sound effects. It's fun. And if you see that hard edge that might give it away so we can go back to our mask feather, soften that edge so it's just not as harsh, and now it just kind of crashes down, which is fine.