Author: Daniel

Lost in Z-Space

So far, we’ve used After Effects for 2D motion graphics and animation work.  After Effects can also be used for 3D work – although there are some caveats.  After Effects is not designed to do 3D graphics work in the same way that programs like Maya, Cinema4D, and Blender are.  You can’t create detailed 3D models or complex environments in After Effects.  However, you can move 2D assets into the third dimension – and create some unique and dynamic results.

This week, we’ll be creating a simple 3D scene.  Download the images at this link if you’d like some media to play with.

From 2D to 3D

You may have noticed a series of symbols at the top of the timeline window, next to the Layer Name column.  If you can’t see them, toggle the view options at the bottom-left of the timeline window.  These symbols represent different properties that can be turned on or off for each layer.  For example, the symbol that looks like a strip of film toggles frame interpolation, which is only applicable to video layers.  The box we want to use looks like a little wireframe cube.  This switches layers from 2D to 3D.

Clicking on this box will probably not make an immediate change to the way your composition looks.  However, if you look at the Transform options for that layer in the timeline, you’ll see that the possibilities have expanded greatly.

Position, for example, was formerly defined by two numbers – a value on the X (horizontal) and Y (vertical) axis.  In other words, that layer could formerly move up-and-down and side-to-side.  With the 3D box checked, a third number has been added – we can now move forwards and backwards on the Z (depth) axis.  The anchor point value has also gone from two variables to three.  Rotation was previously described by a single number, but now objects can be rotated three ways.  There is also a new “Orientation” value, which provides another set of rotation values.  Scale has gained a third number as well, although the new Z-scale value won’t generally affect 2D layers.

3D Rotation

Let’s look at the rotation values first.  X Rotation spins an object around a horizontal axis, Y Rotation spins around the vertical axis, and Z Rotation spins around the depth axis (2D layers can only spin around the Z axis, so X and Y are the new options).  The best way to understand how these work is just to take some time playing with the values.  Remember that layers rotate around their anchor points.  So, if you want an object to swing open like a door, you’ll need to move the anchor point to the side of the object and keyframe the Y Rotation.  If you don’t change the anchor point, the object will spin around its own midpoint.

X, Y, and Z Rotation each have their own section under the Transform properties.  The Orientation section combines all three into a single keyframe-able value with three numbers.  I tend to use the individual Rotation values more than Orientation, but they both do the same thing.

It is possible to work with both 2D and 3D layers in the same composition, but they don’t really “interact” with each other.  If you rotate a 3D object so that it intersects with another 3D object, one will be “clipped” by the other.  A 2D object will simply float in front of or behind a 3D object, depending on its layer position in the timeline.

3D Position

When you click on a 3D layer, you will probably notice a new icon appear in the composition window.  This icon is comprised of a green, red, and blue arrow, centered on the anchor point of the layer.  You can click and drag on the green, red, and blue arrows to move an object along the X, Y, and Z axis, respectively.  You can also change these values using the three numbers that now appear next to “Position” in the layer’s transform properties in the timeline window.

Entering a positive value for the Z position (the third number) will push the layer further away; entering a negative value will pull the layer forward in 3D space.  This may be somewhat counter-intuitive, so take some time to familiarize yourself with it.  To create a very simple 3D scene, you might enter a positive Z position value for the background layer, a negative Z position value for the foreground layer, and 0.0 for the Z position value of the middle layer.  As these layers get moved along the Z axis, their size will appear to change.  You can compensate for this by adjusting the scale.

This can give us a nicely layered composition, but so far, we haven’t done anything we couldn’t do by adjusting the scale and position of 2D layers.  For example, you can make an object appear to move closer by increasing its scale.  So why use 3D position?  One reason is that it can be difficult to estimate the way that scale and position should correspond.  The other reason has to do with perspective and an effect that we can achieve only by using 3D layers – but for that technique, we’ll need a virtual camera.

A Virtual 3D Space

In our 2D work, we used the After Effects composition window sort of like a collage board; flat layers were placed on top of each other, rearranged, and adjusted.  When we switch layers from 2D to 3D, that collage board becomes more like a shadow box; objects can move forward and backward in space.  Our perspective on the shadow box hasn’t really changed, though – our view is fixed.  By adding a camera to the scene, we can change our perspective and even move into the scene itself, going from a shadow box to a complete virtual environment.

To create a camera, go the the Layer dropdown menu at the top of the screen and choose New>Camera….  This will bring up a dialog box with lots of options.  You can dig into these values and customize your virtual camera as much as you like, but I’d recommend leaving most settings at their defaults, at least to get started.  The one thing you may want to adjust is the Preset, which has a handful of simulated lens options.  These act just like lenses on real cameras: wider lenses (lower numbers) have a larger field of view and Z axis movement will be exaggerated.  Longer lenses (higher numbers) have a narrower field of view and Z axis movement will be compressed.  If you aren’t sure what to use, either the 35mm or 50mm presets are generally safe, middle-of-the-road options.

After you create your camera, you may notice an immediate difference in the scale of the objects in your composition.  This is because of the aforementioned properties of the lens on your virtual camera.  If you tip down the triangle next to the name of your camera layer in the timeline, you will see Transform properties and Camera Options.  The Camera Options section contains a ton of variables to play with – you can define the virtual depth-of-field, the shape of the simulated iris, the size of the aperture, and much more.  

Turning Depth of Field “on” is probably the setting that will give you the most interesting results.  Depth of field describes how much of an image is in focus.  If a scene has a deep depth of field, lots of things at various distances from the camera will be in focus.  If a scene has a shallow depth of field, only a narrow sliver of the scene will be in focus.

If you have some experience with photography, those basic principles will help you as you define things like focal length and depth of field in the virtual cameras that After Effects uses.  For example, you may be aware that a lens with a large aperture produces images with a shallower depth of field than a lens with a small aperture.  Increasing the Aperture value in After Effects (which is measured in pixels) will therefore give you a more blurred out background when the Depth of Field toggle is enabled.  For reference, the Aperture in the image above is around 400 pixels and the lens is 50mm.  If this is unfamiliar to you, you may just have to experiment with the controls a bit to get the results you are looking for.

Moving the Camera

The Transform options control camera movement.  You can keyframe the rotation along all three axis, either individually or using the Orientation.  The position works the same as other 3D layers, but there is also a keyframe-able Point of Interest property.  This is the point that the camera is aimed at; so, for example, if you keyframe the camera’s position along the X axis, but don’t adjust the Point of Interest, the camera will move from one side to the other while remaining aimed at the center of the screen.  You can get some cool results this way, so take some time to play around.

 In addition to the control options in the timeline window, you can adjust your camera using a section of tools in the toolbar at the top of the screen.  The default option is the “Unified Camera Tool” (which looks vaguely like a movie camera), but there are several to try out if you prefer more “hands-on” control.

If you’re having a hard time visualizing how exactly your camera is moving, it can be helpful to change the view setting of your composition window.  At the bottom of the window is a dropdown menu that, by default, reads “Active Camera.”  Clicking this will give you different options for viewing your composition in 3D space.  In particular, Custom Views 1, 2, and 3 are helpful for seeing how your camera is positioned and where it is pointed.  Note that you may need to toggle the background visibility on or off (the checkerboard icon next to the view setting) and/or zoom out your view to see what’s going on clearly.  Just switch back to “Active Camera” when you’re done.

There are many more things to explore when it comes to 3D work in After Effects.  You can create different kinds of virtual lights, control the way simulated shadows are cast, affect how shiny or matte objects are, and so on.  For now, though, just get used to moving objects in 3D space and operating a virtual camera – it will open up a whole new world of creative possibilities.

Optional Assignment: 3D Scene

I want you to be able to focus on your final projects right now, so I’m not assigning a project this week.  However, if you have a missed assignment from sometime during the semester and would like to make it up, you can create a five to ten second composition that uses 3D objects and a moving camera.  Render it as a 1920 x 1080 QuickTime movie using the H.264 codec, upload it to your Google Drive, and send me a download link.

Coding Animation

If you’d like some media to use for this lesson, you can download some fun Victorian-style woodcut art at this link.

Adding keyframes is one way of animating properties in After Effects, but there is another method as well – using expressions.  An expression is essentially a line of simple code that is applied to an animatable property.  It’s not the same as writing computer code – you don’t need to know any specific programming language, or anything like that – but the idea is similar.  To add an expression to a property, alt-click on the stopwatch icon that you usually use to turn keyframes on and off.  The value associated with that property will turn red and a box of text will open in the timeline window.  That window is where you add the expression.

Probably the simplest kind of expression – and one of the most useful – adopts the value of a property on another layer.  For example, you could take the rotation value of one shape and apply it to the rotation of another shape.  When you create an expression, four small icons will appear, one of which is the swirly “pick-whip” icon that we previously used to parent layers.  If you use the pick-whip to select the rotation property on a different layer and then hit “enter” (or click outside the text box), whatever value is entered for that layer will be used for the layer with the expression.

I realize that may sound confusing, but it’s fairly simple in practice.  It means that you can animate a single layer and use it to affect other layers.  Simply animate the first layer, then use an expression on the others.  Try it out – once you get used to the process, you might find yourself using this particular expression a lot.

One small thing to keep in mind as you are entering expressions: the “enter” and “return” keys do different things.  One (enter) closes the text box, the other (return) adds a line to the current expression.  You can also close the text box by clicking outside of it in the timeline.  If you want to remove an expression, alt-click on the stopwatch icon again and it will return to normal.

Math

One thing that’s neat about expressions is that they can be easily combined or modified.  If, for example, you wanted to use the rotation expression above, but make the layer with the expression rotate the opposite way of the layer it gets linked to, that’s very simple.  Just use the pick-whip to select the layer with animation, then type *-1 (multiply by negative one) after the expression in the text box and hit “enter.”

This technique can be very helpful for things like animating a bird flap its wings, since you can animate both wings with one set of keyframes.  Furthermore, any changes you make to that set of keyframes will automatically affect both layers.

There are a lot more expressions that you can use to automate all sorts of properties in many different ways.  One that you might come across uses the timecode of the composition, often multiplied by a number.  If you add an expression to the rotation property of a layer and type time, the layer will rotate to one degree at the one second mark, two degrees at the two second mark, etc..  If you type time*100, it will rotate to 100 degrees at the one second mark, 200 degrees at the two second mark, etc..  This is a simple way to add continuous animation to a property, regardless of the length of the composition.

Get Random

I’ve been using rotation in my examples so far, because it’s an easy property to visualize.  Anything that can be keyframed can be affected by an expression, though – opacity, position, scale, and even the individual parameters of effects.  One of my favorite expressions, wiggle, applies random values within certain limits.   It can be used, among other things, to create unpredictable, organic-seeming movement when applied to the position of a layer.

To add wiggle to the position of a layer, alt-click on the Position keyframe icon in the Transform properties.  A text box will open in the timeline – in it, type wiggle, then two numbers in parentheses, separated by a comma.  For example: wiggle(2,150).  The first number in this expression is the frequency: 2 equates to two times per second.  Entering a 3 would be three times per second, and entering .5 would be half a time per second (or once every two seconds).  The second number is the amount to move.  So, our position expression “wiggle(2,150)” will move an object up to 150 pixels along the X and Y axis, twice per second.  If our layer were 3D, it would move on the Z axis as well.

Of course, you don’t always want random movement, but it’s occasionally extremely helpful.  I’ve used the wiggle expression to animate everything from fireflies to dials on a car dashboard.  You can even apply a wiggle to a virtual camera to simulate the look of handheld footage.  Randomness is more powerful than you might initially realize.

I mentioned last week that wiggle can also be applied using an animation preset.  These are found in the Effects & Presets panel (the same place we found the text animation presets earlier in the semester).  If you type “wiggle” into the search bar, you’ll see a few different options there.  The wiggle animation presets still use expressions, but they sort of do the coding for you.  The presets work in conjunction with the Transform effect (in the Distort category), as opposed to the transform properties in the timeline panel.

Expressions open up a vast new world of possibilities in After Effects.  The icon to the right of the pick-whip opens a window that contains dozens of “building blocks” – presets and pieces of expressions that can be combined to make very complex automated effects.  Don’t feel like you need to understand what each of these does – instead, just get comfortable applying expressions.  Often, online tutorials and trainings will provide expressions for you to copy and past into your own compositions.  Like so much of After Effects, once you are familiar with the process, you can figure out the specifics as you go.

Project 7: Express Yourself!

Use expressions to create a composition between five and ten seconds long.  You may use the provided media, your own files, or something you find on your own.  Use at least two expressions; you may also use keyframes.  Export the composition as an H.264 QuickTime movie, upload it to your Google Drive and send me the download link.

Note that storyboards for the final project are also due next week.  These can be very simple – stick figures are fine – but they should illustrate your plans for the film.  The full details of the final project are at this link.  You can either email me a copy of your storyboards or just bring them to class next week.

Find Yourself

It’s time to start thinking about the final project!  The parameters of the final project are very similar to those of the midterm: create an animated short film based on a given theme.  For the final project, that theme is “Lost & Found.”  Here are the details:

• You should incorporate the theme in some way, but you can interpret it however you wish.  It’s really just meant to be a starting point for you to build upon.
• Ideally, your finished film should be around one minute long, but there is some flexibility in the total running time.  Thirty seconds should be the absolute minimum and if you want to go a bit longer than one minute, that’s fine.
• You can create puppets and background from scratch or find already existing media to use – but that media should be royalty-free.  Don’t use copyrighted stills, video, or music.  If you need help finding royalty-free media, check out the RESOURCES section of the blog or contact me directly.
• You may also repurpose puppets, props, or backgrounds you’ve already made for this class, but the finished film should be distinct from your mid-semester project.
• You are not required to, but you may incorporate spoken dialog into this project.  If you’d like help with lip syncing animation, let me know.
• The final output should be a QuickTime movie (H.264 codec) with a resolution of 1920 x 1080 and a frame rate of either 24 or 29.97.

As always, be creative and have fun with his project.  I’m not requiring you to use any particular techniques, so come up with the project you want to make and use whatever you feel would be best for it.  If you can’t figure out how to get a particular effect, I’m happy to help.

Here’s the timeline for this project:

4/5  Discuss final project details in class

4/12  Storyboards due

4/26  Final projects due