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Update:  Several of you have written to suggest that I do the videos for this series.  Thanks for your input -- I'm working on the videos and project files, and I'll post them at the top of the related blog entries as soon as they're ready!

In the previous part of the 3D in Motion series, we discussed the very basics of manipulating Motion layers in 3D space.  We moved them and rotated them, and now it's time to go one step deeper.  Our goal in this lesson is to understand how to "fly around" in 3D scenes, using cameras and 3D layers.

Background and Concepts

To get the concepts down, let's step back a little bit.  As you were moving objects around in 3D space in Part 1, it might have occurred to you that the X, Y, and Z arrows are a little bit pointless (or at least awkward, when you're trying to get things where you want on the screen).  I mean, think about this situation: I've rotated my layer in 3D to where it takes the perspective I like, and it's in the top-right corner of my canvas, where I want it.  But I just want it to be a little bit ... bigger.  I could use the object's 3D Transform Arrows to move the object closer to me in 3D space -- but why not just use the Scale controls to "zoom it up"?
The answer, of course, is that scaling the object rather than moving it changes the way that object relates to other objects in your scene.  An easy way to think about this is to visualize that scaled-up object (Object A) crossing the path of another object (Object B): if I made Object A bigger by moving it closer to my point of view, then Object A will cross on top of Object B from my point of view.  If instead I scaled Object A up while leaving it "off in the distance," Object B might cross through or pass on top of Object A -- which probably isn't what I expect to happen.

There's one very important kicker: when I talk about the way the object "relates to other objects in the scene," one of the "other objects" that I'm talking about is the imaginary "camera" or "set of eyes" that we're looking through to create the picture on screen.  When you're working in 2D, the Canvas itself is the point of reference that layers relate to -- after all, they're 2D, the picture's 2D, so no problem!  But when you're working in 3D space, the Canvas is still just as 2D as it ever was -- tap on your screen a couple of times; it's still flat, right?  Just like shooting a camera in the real world, you have to strip out some of the information about 3D objects in order to represent them in a flat, 2D view.

240px-Hexahedron.svg.png This point can be difficult to understand, but it'll hopefully make the process of working in 3D much more clear.  Think about some of those old optical illusions.  When our brains imagine 3D-ness from a flat picture, they make some assumptions. For example, one way we judge distance is to decide whether an object looks bigger or smaller than we expect it to, compared to other objects in the scene.  One way we judge whether an object is facing us is whether its lines are straight -- skewed lines (like in the cube to the right) make us assume that an object is rotated relative to us.  And if you think about it, you could use plain 2D tools to draw the shape of the cube: just create a few solid layers in Final Cut, and use the Distort tool to make them skewed.  To be perfectly clear, then, showing video layers in a "3D" perspective on screen means simply translating objects' imaginary 3D positions into the correct distortions to apply to the original, flat video layer.

In order to determine what those "right" distortions are, the computer has to understand how your 2D "camera" is looking at all the rest of the imaginary 3D world.  And in order for THAT to happen, there has to exist a 3D "world" outside of the camera itself -- and the camera has to be able to move around in it.  Hopefully that explains why moving objects in 3D space is different from rotating and scaling them -- and it's probably enough to understand cameras in Motion on your own!

In the practical section for today, we'll create a couple of layers, and then create a camera to look at them.  We'll begin to learn Motion's (really great) interface for moving around 3D space, and I'll suggest some questions to explore between now and the next part in this series.

Practical

  1. Let's pick up where we left off in Part 1.  You should have a 3D layer or two in your scene, and you might have manipulated those layers some.
  2. Now, it's time to add a Camera to the scene: click the New Camera button (it's with the buttons at the top-right of the screen).part2-add-new-camera.png
  3. Check under the "View" drop-down box to make sure that the default settings for 3D View are checked.  Each of these settings affects the "helper" wireframes that appear in your 3D scene while you're previewing it.part2-check-view-menu-options.png
  4. When your camera is selected in Project Pane...
    part2-camera-selected-in-project-pane.png...you'll see some Camera Transform tools at the top-right of your canvas.
    part2-camera-controls.pngTo use these controls, click and hold on the one you want, and drag your mouse to use it.  Release the mouse button when you have the camera facing where you want.  If you get lost using one of these controls, double-click on the control to reset it to the default.
  5. Take a moment to look around the 3D interface. 
    • The 3D Grid that you see on your Canvas illustrates what's called the "ground plane."  What does that mean?
    • Click on one of your layers, and start transforming it in 3D.  Notice that you still have your Camera Transform Tools at the top-right of your canvas: you can very easily go back and forth between changing the camera's view and changing the actual layers in your scene.
    • Pick one of the 3D layers in your scene, and duplicate it (Cmd+D while the layer is selected).  Use the 3D Transform Control on your new layer to arrange the new layer at a right angle to the first layer.  Use the Camera Transform Tools to orbit around your scene and make sure you're lining up the layers at the right angle.
      part2-multiple-layers-right-angle.png
  6. As long as your Camera is selected in the Project Pane, you can find the full range of Camera controls in the Inspector and the Heads Up Display (HUD).  The Move, Rotate, and Scale controls in the HUD work just like the Camera Transform Tools in the Canvas: click and drag to adjust them.  
    part2-inspector-and-hud.pngYou can learn about most of them by playing around, but I will highlight the Camera Type control.  There are two types of camera here: Framing or Viewpoint.  The type of camera affects how all of the 3D Transform controls work on the camera.  A Framing Camera (the default) is looking at a point of interest -- in this case, the middle of your scene.  When you use the 3D Transform controls, you're having the camera move in relation to that point of interest -- so, for example, the Orbit Tool will make the camera rotate around the point.  But with a Viewpoint Camera, the same tool would rotate the Camera itself -- not keeping the same subject material in the frame.

    Play with both types of Camera: the only way to really get a feel for the tools is by using them.  And don't worry, we'll revisit the difference between Framing and Viewpoint Cameras later in the series.

Questions To Explore

I hate to sound textbook-y, but I seriously think you'll get more out of trying these than reading my wordy descriptions.  I'll discuss them at the beginning of the next part of this series.

  1. In Motion, groups are either 3D or they're flat.  But you can have multiple groups in one project, and you can set some groups to 3D while leaving others flat  How does Motion show a scene where both 2D and 3D groups are visible?
  2. Since a Camera in Motion behaves just like a real-world camera on-set, you can do normal camera things with your imaginary Motion Camera.  Each of these pairs is similar, but different in an important way -- how would you do each in Motion?
    • Dolly vs. Zoom (or Field of View)  [Note: the "Scale" option in the HUD actually dollies your camera instead of "zooming" it.  To play with Field of View (for now), use the Angle of View control in the Camera Inspector.  This will be more clear in the next lesson.]
    • Truck vs. Pan
    • Crane vs. Tilt
  3. In addition to the basic Camera controls that you see in the Heads-Up Display, Motion offers many advanced controls that you can view in the Inspector.  Some, like Field of View, correspond to "real world" camera controls.  Others are specific to the 3D world.  What do Near Plane/Far Plane and Near Fade/Far Fade do, and when might they be useful?  You can find those controls in the Camera Inspector when the Camera is selected in the Project Pane.

Next time -- we'll discuss these questions, and introduce Camera Behaviors.  On down the road, we'll talk about conventional 3D views, and we'll start digging into how Motion's Behaviors, Particles, and Replicators work in 3D space.  It only gets more fun from here.

comments  

JoeFactor said:

Correct me if I am wrong, but this stuff can't be done in older versions of motion (such as 2.12 which is what I have). I can't find any of the buttons (like the camera), in my version. In order to do this stuff would I need the newest version of motion or is it possible to still do it with mine?

Alex said:

Hi Joe,

You're absolutely right. 3D was introduced in Motion 3, which comes with Final Cut Studio 2. Unfortunately, the only way to get 3D in your version of Motion would be to "fake it" with distort controls.

You could upgrade now, but I'd also point out that it's been a while since the current version came out. If going to 3D isn't a pressing matter for you, it might be worthwhile to wait until the next version of Motion/Final Cut Studio comes out -- given the amount of time that's passed, I think it'll be a major and compelling update.

-Alex

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Using the Hand Tool in Final Cut Pro was the previous entry in this blog.

Using the Distort Tool in Final Cut Pro is the next entry in this blog.

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