March Meeting Notes

Tue, 02 Apr 2013 10:53:42 GMT

Work Smarter, Not Harder: Solids and PreComps

Wed, 02 Jan 2013 07:09:00 GMT

Holiday Break

Thu, 20 Dec 2012 11:39:19 GMT

Work Smarter Not Harder: CODECS and Project Organization

Mon, 26 Nov 2012 11:08:07 GMT

Work Smarter Not Harder: Using Images

Mon, 12 Nov 2012 10:47:28 GMT

August 2012 Meeting Notes : Financial Matters

Thu, 30 Aug 2012 10:31:57 GMT

July - August 2012 Animation Challenge

Tue, 29 May 2012 10:58:58 GMT

April 2012 Notes: Cinema 4D to AE

Wed, 09 May 2012 11:41:27 GMT

May Motion Graphics Challenge

Tue, 01 May 2012 07:34:36 GMT

Auto-Typing for Expressions

Mon, 16 Apr 2012 14:09:48 GMT

Title

Auto-Typing for Expressions

Entry

I animate with keyframes when I'm using After Effects, but I totally respect the power of expressions. I've been studying expressions since around 1999, and I have realized that there are so many problems that can be solved through expressions and math.

AAAHHHH!!!! MATH!!! I know. I almost panic every time I even think that I'm learning math-- more math than I ever knew in school.

The problem is that frequently there are things math and expressions can solve that aren't practical with keyframes. I'll set up an analogy for you.

Image

More

AN ANALOGY:

There are times when I'm walking through my house and see a bit of dirt on the floor, I pick it up. However, that is not a very efficient way to clean the whole floor. Some very smart folks spent a lot of time and energy to create a vacuum cleaner. If I disregard this magical invention and clean my carpet by hand, I am not taking full advantage of my time and the technology.

DON'T FREAK OUT!

I'm not going to force you to learn expressions or go back to school for math. But I do want to give you some tools that can help you in your adventure into expressions. The biggest tool I can give you is a way to make expressions a little easier to access.

I frequently use expressions that others have created or expressions that are just useful for a wide variety of projects. Something I had done for years was to either keep these expressions in a "notes" application like Evernote-- web-based so it follows you wherever you go-- or by just doing web searches and visiting sites I know that already have expressions built for certain purposes.

Motionscript.com is a great place to find expressions and learn how to write them yourself. And it's not the only site out there so I've included some links below.

I found myself going back time and time again to certain expressions like simple position expressions, inertial bounce, and a nifty bit of code that makes a layer invisible when facing away from the After Effects camera. At that point, it became clear that I was spending far too much time searching for or rewriting code that I used frequently. The answer was to get an auto-typing application.

AUTO-TYPING

TextExpander for Mac ($35 USD) from Smile Software-- and other apps like it-- can insert blocks of text based on simple text triggers. TextExpander isn't the only Auto-Typing app out there. Kissphrase (http://www.chimoosoft.com/products/kissphrase/) is a FREE auto-typing tool for the Mac. It's not as full-featured as TextExpander, but it works pretty well. And I'm sure there are some good Windows equivalents. I'll provide a list, but can't really vouch for the Windows apps. Anyone who has any suggestions should feel free to leave those in the comments.

At this point I feel like I should offer up some practical uses for these Auto-Typing applications. For example, if I were to type "xxy", I would get this:

x = value[0];

y = value[1];

[x, y]

If you've started to lose consciousness from all the nerd-speak, be encouraged. Auto-typing apps can help you in other ways, too. They are great for long email signatures, web addresses, and other things you find yourself typing frequently-- and you can use them as auto-correct! So when you type "wierd" it would always be corrected to "weird" or "thot" would be expanded to "thought". When I type "tA" on my system, TextExpander removes the "tA" and replaces it with "Trent Armstrong".

A great tip I learned from the TextExpander blog was to put a little identifier with each trigger. It's best to not have your triggers actually spell words that you might use in other contexts, of course. So all of my email signatures are a 3-4 letter prefix with the suffix "sig".

"aeugsig" equals:

Trent Armstrong

Founder - The Dallas After Effects User Group

http://www.dallasaeug.com

214.695.2623

@AETrent

My expressions all start with "x"! So that cool expression I referenced earlier where the layer turns invisible when facing away from the camera has the tag "xinv" (invisible when facing away from camera) and produces this block of text:

if (toCompVec([0, 0, 1])[2] > 0 ) value else 0

And "xbounce" is for the Inertial Bounce expression that can be found at : http://mograph.net/board/index.php?showtopic=13954

NOTE: One really neat thing about TextExpander is that it will drop in the text and then put the cursor where I want it so I can go about quickly updating the expression.

With all that said, I would encourage you to two things:

1) Check out some of the Auto-Typing applications to see if one might be helpful for your workflow.

2) Give expressions a chance. You don't have to fully get expressions to take advantage of them. And then more you use expressions in After Effects, the more you will understand about them.

TIP: To apply an expression to a transform property in After Effects, opt or alt+click on the stopwatch.

EXPRESSIONS:

Here is a collection of expressions that I use frequently enough to put into my Auto-Typing program. Yes, I do have a few more that I use, but I don't want to completely destroy your will to live.

Make a Layer Invisible When Facing Away from the Camera

It's great for flipping text, coins, etc. where you need something besides the reverse of your layer to be on the "backside".

Code

if (toCompVec([0, 0, 1])[2] > 0 ) value else 0

EXAMPLE: http://www.ignitermedia.com/mini-movies/2308/Why-I-Call-It-Good-Friday

Loop a Set of Keyframes

This helps me with looping motion or even time-remapped footage.

Code

loopOut("Cycle",0)

EXAMPLE: http://www.ignitermedia.com/loops/1893/Red-Paper-Clouds

Inertial Bounce

This guy has become really popular lately. When a motion reaches the last linear keyframe, this expressions does a sort of rubbery bounce that can be seen in our Igniter Video "It's Not Over".

Code

n = 0;

if (numKeys > 0){

n = nearestKey(time).index;

if (key(n).time > time){

n--;

}

if (n == 0){

t = 0;

}else{

t = time - key(n).time;

}

if (n > 0){

v = velocityAtTime(key(n).time - thisComp.frameDuration/10);

amp = .05; // How big is the bounce?

freq = 2; // How fast is the bounce?

decay = 5; // How quickly does the bounce stop?

value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);

}else{

value;

}

EXAMPLE: It's Not Over - http://www.ignitermedia.com/mini-movies/883/Its-Not-Over

AUTOTYPING APPLICATIONS:

Here are the two Mac AutoTyping applications that I can recommend.

TextExpander - http://smilesoftware.com/TextExpander/

Kissphrase - http://www.chimoosoft.com/products/kissphrase/

For Windows users, I did a Google search:

Typinator - http://www.jitbit.com/autotext/typinator-for-windows/

Autotext - http://www.jitbit.com/autotext/

There may be more for both platforms, but that's a good place to start.

EXPRESSIONS REFERENCES:

• Dan Ebberts' MotionScript - http://www.MotionScript.com

This site has great case scenarios and snippets you can just drop right into your projects, but this is also where I got my basic foundation in understanding expressions.

• JJ Gifford's Intro to Expressions - www.jjgifford.com/expressions/basics/index.html

This is a great reference for some cool math that can be used in expressions and how expressions can change the way you interact with layers. He has a great quote on there, too! "When Not to Use Expressions-- Anytime you can avoid them."

• AEnhancers Forum - http://aenhancers.com/

This site can lean a little more to the advanced side of expressions, but also has some good old standard expressions.

• Pro Video Coalition - http://provideocoalition.com/index.php/cmg_keyframes/story/after_effects_apprentice_video_tutorial_5

Introduction to expressions by Trish and Chris Meyer

• Javascript Reference - http://www.w3schools.com/js/default.asp

Expressions are based on the Javascript language with a few extra functions that are built-in specifically for After Effects. When I have a question about how to make something happen in expressions and there is not a direct After Effects command, w3schools usually has the answer. It's particularly useful for working with Source Text.

Keywords

autotyping, auto-type, expressions, after effects, math, keyframes

File

Dallas After Effects User Group - Blog

March Meeting Notes

Work Smarter, Not Harder: Solids and PreComps

Holiday Break

Work Smarter Not Harder: CODECS and Project Organization

Work Smarter Not Harder: Using Images

August 2012 Meeting Notes : Financial Matters

July - August 2012 Animation Challenge

April 2012 Notes: Cinema 4D to AE

May Motion Graphics Challenge

Auto-Typing for Expressions