Cameras and Camera Animation
In one sense, working with cameras in Maya is particularly easy, since it is easy to maneuver and manipulate your camera in the virtual world, free of the real-world constraints that make camerawork difficult. However, elaborate camerawork can be disorienting and distract from your scene, so it’s important to strike the right balance of interesting but relatively straightforward camera animation. Be creative, but not wild, otherwise your scene might even become nauseating to watch.
Types of Cameras
Maya provides three types of cameras to use, in increasingly level of control and complexity. The basic camera is just called Camera, and is a single object that you can transform in the usual ways. This basic camera is very easy to work with and sufficient for most uses. The next type of camera is called Camera and Aim, which gives you a group consisting of two nodes of control. You have the camera itself, which you can transform but not rotate, and its aim target, a locator which controls where the camera points. So you can do things like leave the camera fixed, but move around its aim, which easily keeps the camera focused on the action in your scene without moving your camera. This type of maneuver would be difficult with the regular single node camera. Lastly, there is a three-node camera called Camera, Aim, and Up, which contains in addition to the aim locator, a locator which controls the up-axis of the camera, so that you have very detailed controlled over the exact orientation of the camera at all times. For our uses, this is actually more control than we want to deal with, so we will stick to the first two types of cameras.
Basic Camera Manipulations
Open the scene called car.mb. This is a simple scene with a car accelerating on a road past a house. We’ll shoot the scene in several different ways, in increasingly complexity. Add a camera to the scene by going to CreateàCamerasàCamera. First, observe that you can translate and rotate the camera just as you would with any other object. This is convenient, but it’s hard to see the effect this has on what the camera can see. Making sure the camera is still selected, click on the Panels menu in your perspective viewport, and choose Look Through Selected.
Now the perspective viewport instead shows what the camera sees. In this view, you can use your viewport manipulation tools (alt + left click, alt + middle click, alt + right click) to affect the camera view, and press “s” to keyframe while you’re doing this. So move your viewport around so that you’re facing the car from the side, and press “s” to set a keyframe.
Now move the time slider over to frame 60, where the animation ends. Pan your viewport over so that the car is once again in view, and when you’re satisfied with the framing of the car, press “s” again to set another keyframe here. Play back the animation, and you’ve got a camera that follows that car, using only 2 keyframes. You could set some intermediate keyframes to get finer control over the camera movement. However, don’t get too carried away with intermediate keyframes—use them sparingly, so that the interpolation will give you smooth camera movement.
Alternatively, we can get a follow-camera in a different way. Delete your camera and/or create a new single node camera as before. We’re going to constrain our camera’s position to that of the car. Then we’re going to apply a little bit of an offset, so that the camera is outside the car instead of in the center of it. Open up the Outliner, and click on the car’s group, called nissan_200SX. Then, ctrl-click on the camera. Now, with the Animation hidden menu set open, go to ContrainàPoint.
Notice the order in which we did this: we wished to constrain the camera to the car, so we selected the camera first, and then the camera. When applying a constraint between two objects, select the Parent first, and then the Child. Now the camera is parented to the car, so that when you play back the animation, the camera moves exactly with the car. But this isn’t exactly what we want, since the camera is stuck to the pivot of the car, which is at its center. Notice now though that in the Outliner, there is a + next to the camera now: it has a constraint node as its child. Click the + and then click on the constraint.
Now open up the Channels Box. We want to edit the offset. Find the field called Offset Y and change it to 5. Change Offset Z to 20. This puts the camera 5 units above the pivot of the car, and 20 units in front of it. Click on the camera and once again go to PanelsàLook Through Selected. Play back the animation, and the camera should now be at a fixed follow distance from the car as it moves.
Cameras and Aims
Now we’ll see how having an aim can be useful. Create a camera with aim by going to CreateàCamerasàCamera and Aim. Open the Outliner and notice that this camera is a group, containing a camera node and an aim node. Select only the aim node and move it around the scene, and notice how the camera pivots so that it is always oriented towards the aim. Place the camera itself anywhere you like to give a good view of the car. Then in the Outliner, select the car group. Then ctrl-click on the camera’s aim node. Once again, make a point constraint by going to ConstrainàPoint. We’ve now constrained the aim to the car, so that the camera will always focus on the car. Recall the order that we selected things again: parent first, then child; otherwise we would have parented the car to the aim node. Click on the camera and go to PanelsàLook Through Selected to look through the camera’s view, and play back your animation. The center of attention should remain fixed on the car even as it moves across the scene. You can also freely move and keyframe the camera node itself, and no matter how it translates, the aim will remain fixed on the car. Also notice that we got the camera to follow the car without creating keyframes at all.
Motion Paths
Since smooth camera motion is important, it’s natural to want to fix our camera to some smooth trajectory that we’ve created. In fact, we can make any curve in our scene into a Motion Path that our camera (or in fact, any object) can follow. Also, motion paths mimic one of the ways cameras are actually used in real life. Oftentimes, to get a smooth shot using a real movie camera, a physical track is built in which the camera can follow on a little cart. The curves we use as trajectories are the digital analogs of these tracks.
First, we’ll create a simple straight track that follows alongside the car. We’ll just draw a straight line for our track. Go to CreateàEP Curve Tool. Then in the Top viewport, click once at the beginning but to the left of the road, and again at the end of the road, creating a straight path that parallels the road. In on of the side viewports, move the curve up vertically, so that it is at approximately the same height as the car.
Create a new single node camera. Then, in the Outliner, select the camera, and
then ctrl-click on the curve to select it as well. Go to AnimateàMotion PathsàAttach to Motion Path, and click the options
box. In the options box, choose
Start/End as the
Play back the animation. The camera moves along the path, but it’s possible that it doesn’t line up with the car. That’s because the car is accelerating, while the camera is moving at a fixed rate. We can adjust this by converting the motion path to keyframes. This is achieved in the same way that we created keyframes from dynamics: by baking. With the camera selected, you can go to EditàKeysàBake Simulation, and click the options box. Set any sample rate that you desire, but in this case, it might be best not to use that many samples. For example, if we sampled by 30 frames, then we would only get 3 keyframes, making them easier to work with. Since our animation is so simple, we don’t lose any significant detail by doing such coarse sampling. In the Graph Editor, we could then manipulate the middle keyframe to give a smooth, accelerating curve. See the Animation tutorial for a refresher.
Combining These Elements: A Sweeping Camera Move
We’ll use all the camera strategies we’ve discussed thus far to make a more interesting camera shot. Go to CreateàArc ToolsàThree Point Circular Arc. This tool allows us to easily draw a smooth, round path. In the Top view, click where you want your path to begin, maybe somewhere in the upper right corner of the viewport. Then click once more for the middle of the arc and third time for the end of the arc. Try to make it surround the scene.
Once again, in one of the side viewports, move the curve up vertically so that it is somewhat above the rest of the scene.
Now create a Camera and Aim again. Once again, select the car group in the Outliner, then ctrl-click to also select just the camera’s Aim node. Go to ConstrainàPoint. Once again the camera’s aim is fixed on the car.
Now in the Outliner, select the camera node itself and then ctrl-click to select the curve you just drew. Go again to AnimateàMotion PathsàAttach to Motion Path, and click the options box. You can use the same settings as last time, with Start/End selected, and then end frame set to 60. However, this time, uncheck the Follow box. We only want the camera’s position to follow the path, not its orientation. It’s orientation will be determined by its position relative to the aim constraint. In fact, if we don’t uncheck the Follow box, Maya will give us an error, because its orientation is already controlled by the aim constraint.
Choose PanelsàLook Through Selected again and play back the animation. The camera should sweep around the scene from above, all the while staying focused on the car as it moves.
Additional Camera Effects
When explosions, crashes, or other hard impacts happen in a scene, it can cause a great sense of realism to shake the camera, since it makes you believe that the camera is there witnessing the scene. Try keyframing the camera rotating back and forth quickly over a handful of frames to get this effect.
Most of what was talked about above involved very smooth camera moves. Some film styles involve a handheld camera, which has an organic, bumpy motion to it. This can be achieved by using dynamics. You can keyframe a cube or simple object moving around the scene to represent your overall camera move. Then inside the cube you can stick a particle, attach it to the cube using springs, and let it jiggle around lightly inside the cube. Then create a camera and constrain it to the particle. See the Dynamics tutorial for a detailed walkthrough of this.
Watch movies closely for how the camera moves. It is often the case that the camera will never stop moving in a scene. You may not notice it until you look for details, but there may be very subtle, continual motion, which adds interest to the scene. A still camera, unless used for a specific effect, is often boring.
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