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- Working with image sequences
- Matching the 3D camera to video footage
- Lighting models in Maya
- Splitting a scene into multiple render passes
- Batch rendering
- Recombining render passes in an After Effects composition
- Setting up motion trackers
- Refining layers with rotoscoping
- Adding blur and effects
- Adjusting shadows and matte edges
- Using color correction
- Stabilizing shaky video
Skill Level Intermediate
One important part of Visual Effects work is rendering out the 3D models so that they integrate properly in the composite. One thing that will help you do that successfully is create an image plane as reference inside Maya. We'll use this scene right here to demonstrate that, this is shot1_start.ma. And this is actually the first step of the first tutorial where we'll combine this 3D model, which is a futuristic spyglass, with a live-action piece of footage of an actress. In fact, we are going to make it look like this device is held by the actress in her hand. So how do you create image plane? Well, first thing we need to do is check a few settings to make sure the image plane is used correctly.
First thing I want to do is check the frame rate of the scene. So I'm going to go down to the Animation shortcut, down here, this bottom right button, click that. It opens up the Preferences window, I'll go to the Settings section in the center, and you see what the frame rate of this scene is. Right now, it's 24 frames per second. Now the video is actually shot in 24 frames per second, so that's a great match, but if you had other footage at a different frame rate, you'd change it here first. Second thing we need to check is the resolution of the project. So I'm going to close this, go to the Render Settings window and scroll down, check the resolution.
Right now, it's set to HD 1080, and that's great because that's a resolution of the video. That's high-definition video, which is 1920x1080, so we're good there. If you have different resolution, you'd change it to match. So check the frame rate, check the resolution, so now we can bring image plane in. Now you have a couple of options in the Image Plane, one is you can bring in the image sequence, or a movie. And movie would be like a QuickTime, or AVI file. An image sequence, which is actually very common for Visual Effects work is a series of numbered frames. Each frame is a whole frame from the video, and that can be exported from a program like After Effects.
So let's say we are bringing an image sequence, and we go up to the View menu for the camera where we want to attach the image plane, in this case, Perspective view. Go to View > Image Plane > Import Image, then go to the Footage folder, go to Shot1, and click on the very first frame in the Image Sequence, and you can see there's a whole bunch of frames here, in fact, there are 60 total. We'll click on 000, open that, and that image comes in as an Image Plane, and that's attached to the perspective camera, or the persp camera. In fact, if I go to another view, like persp1 here, and zoom out, you'll see that that plane is attached to the persp camera.
Now it's not quite useful yet, one problem is I only have one frame of that entire image sequence, if I scrub the timeline, it doesn't move, nothing changes. What I have to do is go to the Attribute Editor for the image plane and make a few changes. If we go back to View and go to Image Plane > Image Plane Attributes and pick the one plane that I have, there are the attributes right here. If I scroll down a little bit there's an attribute called Use Image Sequence. If I click that, it tells Maya to automatically load the frames as you go across the timeline.
In fact, what it does is writes an expression that relates the time to the number of the frame. Now in this case, it's a little bit off, I was to scrub all the way to the end to frame 60, the image plane disappears, that's because the frames were numbered 0 to 59. Luckily though, there is Frame Offset which I can change -1, and I'll change that relationship. So what that means is if I am on frame 60, actually load frame 59, 60 minus 1. When I am on frame 1, it tells it to load frame 0, which is 1 minus 1.
So now we have the sequence loading up one frame at a time. Another problem though is the fact that the 3D model has disappeared, and that's because the image plane is actually in front of it. What we can do though is go back to the Attribute Editor for the image plane, go a little bit further, and there is a Depth Attribute. If I change that Depth Attribute to a higher number, such as 500, it pushes the plane further from the camera, and therefore behind the model, so now we can see that. Now, as we look at the view, right here we can see that the image plane might be a little cut off.
One thing I can do to make sure I see the edges of the image plane, is go up to the View here, go to the Camera Settings and turn on the Resolution Gate. The Resolution Gate will show me the entire frame, and the green line in this case shows me the edge of the render. So now I can make sure I can see the entire thing. So let's try a test render and see what this looks like. With the Perspective camera activated, I'll go up to the Render view shortcut and render out a frame, that's a big resolution, so I'm going to scale the Render view down a bit first, and take a look.
And there indeed is the 3D model in front of the Image Plane, so it's great for reference. Now one problem is, is it's permanently there until I hide it. Eventually, when we render this out, we don't want that there. So there's a way to turn it off just for that view. If I go back to the Attribute Editor for the Image Plane, go up to the top, there is an attribute called Alpha Gain. If I turn that to 0, it hides it from the Prospective view. If I re-render it now, you will see the Image Plane is gone and another good thing is the Alpha Channel is correct, I'll go up to the Alpha Channel, the Alpha is there just for the model, but not for the Image Plane.
Okay, so far we have set the Image Plane based on image sequence, based on some video footage, so we're ready to move on to the next step, where we'll position the camera to make sure that the perspective lines up, so the model better matches the footage.