Join Craig Whitaker for an in-depth discussion in this video Creating a mock-up, part of VFX Techniques: Creating a CG Flag with After Effects and CINEMA 4D.
So, here I have one frame from our final shot, the footage. And let's put, what we're going to do is we're going to jump in and we're going to make a mock up of our flag animation. Now this is going to make each step of the process much easier. It's going to help direct everything from scale, position of the flag, how we light it, how it's integrated into the final shot. So, here's how to Photoshop. We're going to look to identify a couple things. First, where are we putting this flag? How big is it going to be? Where is it going to be, you know, fixed to the bridge? Where is the light coming from? What are our shadows going to look like? What is the shading going to look like on the flag? Are there any objects that we may need to create later in 3D to interact with the flag.
So this mockup's going to really help us. It almost functions as a to-do list as we move through the production pipeline. So, I'm going to make a new layer, bottom right hand corner and I'm going to hit B to activate my Brush tool. I have this purplish color here selected. I'm going to click once on top of the bridge where I want it to start. I'm going to click here and then I'm going to hold down Shift and click the second point down here. Maybe up here a little bit. It's going to draw a straight line for me. And then I'll click here, I'll hold down Shift over here.
Click here, shift up here for another straight line and then here, shift again and make a straight line. And this is all very, very loose, I'm going to right click, take the hardness up to a 100 and kind of fill this in. Again very, very loose, I could probably even make this a little messier than this, but why do that? So let's fill this in with purple here. Okay? Great. So that's our flag. So now let's make a new layer and I'll go to grab a red color.
Let's start identifying the direction of the sunlight in the shot. Let's turn off the flag. Now, the best way to do that is, well obviously, the best way to do it is if you can just clearly see where the sun is in the sky. Here its kind of blown out in this upper right hand corner and the next thing we can do is look for some shadows on the ground that will help. So if I look over here, all along this walk way I can see shadows. Right here on every little post. Now it's kind of subtle, but you can see it. So it's helping me it, it's, it's kind of confirming that the sun is where I thought it was, in the upper right-hand corner of the shot.
So that's where we'll have our key light kind of in, up in this direction. All right, so this'll be our key light, which means that I'm going to have to have light from the opposite direction. So maybe over here, maybe off the ground. This will function as our fill light, filling in all of the dark, shadowy areas. Last will be when the flag is at the top, before it unfolds, we'll need some light from this direction that will function as sort of like a rim light just to kind of light up the front of the flag before it comes down.
All right. Let's make a new layer. Grab a different color here. Now, in this shot, the flag starts at the top and then we drop it or essentially unfold or unfurls, it's going to come down and when that happens in 3D, Cinema 4D has no idea that our footage has a bridge here so this flag could, in theory, go backwards. Farther than we want it to when we composite it into the final shot. So, what we're going to need to do later in 3D is build a little piece of geometry here that functions as our bridge, right.
This will be our collider object. So when the cloth unfolds, when the flag comes down, it knows to bump into something, right. So we're going to have to build all that stuff later. So, this is basically saying hey, don't forget you're going to need to build something for this flag to collide into. Next, I'm going to start looking at scale. Which is very, very important. All right, so let's grab this blue brush here and I'm looking at the footage, now based on other objects in the shot, and just kind of taking an educated guess, I'm going to assume that the distance between this and this is about 180 cm.
All right, so all these I'm guessing are roughly 6 feet apart. So, if I turn the flag layer back on. Let's drag that on top. I'm going to then say, from here to here is roughly 1,000 centimeters. Now don't take out your calculators and start doing the math here, I'm rounding up to a nice, even number to make it easier on myself later. And I know that I want the flag, top to bottom, to be twice that, so we'll say this is about 2,000 cm and now you're left with a very pretty looking Photoshop document.
Last, I'm going to pick this purple color again for our flag and I'll just make it a little bit darker, something like this. And with a soft brush, just quickly kind of make some sketches of, you know, where I want this to appear darker. And again, this is all very, very rough. We'll just kind of, using as a guide, that I know I want the shadow area to be down here, and our can be up here, so this side of the flag is going to have to be darker, this side is going to be a lot brighter, I want the light to fall off top right to bottom left.
So let's go for our Eraser, set this to a soft edge, and just try to paint away some of that like that. So, now we kind of have this gradient going from the upper right hand corner to the bottom left. So now we have a mock up. We've clearly established our scale, our lighting direction, any objects that we're going to need to create later in 3D, so when we get to that point, our to do list is much clearer and as we move through the production process we have a very clear idea of what we need to execute.
- Collecting reference materials
- Planning and blocking out the shot
- Analyzing and tracking the footage
- Solving the tracked shot and setting up the environment
- Creating and adjusting the cloth simulation
- Texturing the flag
- Rendering passes from 3D
- Color grading, adding grain, and working with lens distortion