11 Frequently Asked Questions about After Effects

Apr 3rd in Articles by Topher Welsh

People love After Effects and for the most part After Effects loves you back. But sometimes you just want to throw it out of the window because you can't understand why something is not working the way you were hoping. In this week's article, Topher attempts to answer some of the more frequent questions that appear in forums and comments.

Author: Topher Welsh

Topher Welsh is a post production artist working mainly in the fields of motion graphics and visual effects. He is a freelancer out of Tacoma, Washington, and also runs www.VisualFXtuts.com, which provides a daily fix of tutorials from any and all applications in the visual effects industry. His personal website is found here: www.Toe-Fur.com.

Hounding forums here and there, I find myself answering and reanswering the same questions over an over again. Things that are so basic, yet most people can't figure them out because they aren't obvious or the answer isn't spelled out for them. Well, I am deciding to do the community a service, noobs and experienced After Effects artists alike... I am sure there is something in here for everyone. We are going to discuss the most frequently asked questions about After Effects.

11 Most Frequently Asked Questions about After Effects

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  Previewing Audio In After Effects

  There are three ways to RAM Preview in After Effects. By pressing the Enter, or Return key, you preview only video. To preview only audio in realtime, press the period key on your number pad. And finally by Pressing the zero key on your number pad, that will preview audio as well as video. A little handy trick to keep your technique toolbox is if you hold contol while you scrub in the timeline, it will play the audio as you scroll over it, forward backward and as fast as you move. Useful Audio Keyboard shortcuts: Tap L once for your audio levels keyframing, tap LL (L key twice fast) it will display your audio waveform.

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  Why do I have a Green or Red X or a watermark in my render or composition window?

  Because you are cheap... No just kidding... you downloaded a trial version of the plugin you are using. A lot of the time this happens with the Trapcode plugins. A lot of new After Effects users don't realize that you can't just download these plugins and use them for free... they do cost money. Which brings me to the next question.

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  Why don't I have the Cycore (CC) Effects?

  Well, the Cycore Effects, or rather CC effects, came bundled with After Effects 7.0 and above. If you don't have them with your installed version of After Effects you can try reinstalling After Effects from the CD's your software came with. Or you could have a look over at cycoreeffects.com. Either way, you should have them on the same disk as your After Effects install disk if you have AE7 or above. If none of those ways work for you, contact Adobe Customer Support.

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  Why doesn't motion blur work?

  I hear this one a lot. First, check to make sure your motion blur switch for the layer is turned on. Then check to make sure that motion blur is turned on for the composition. If both of those aren't working, I am guessing you are using a CC effect like CC Particle World, and the motion blur still isn't working. In that case you can apply CC Force Motion Blur to an adjustment layer over the top of your composition's layers or you can precompose the layer and then apply CC Force Motion Blur directly to the presomposed layer. Reason being, because if you apply CC Force Motion Blur to a layer with other effects, it disables those other effects. This is also a handy tool if you are looking to apply motion blur to only certain layers, or keyframe when the motion blur happens.

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  Rendering vs. Exporting

  My basic rule of thumb: NEVER use the File>Export function. I personally think they should do away with it, but until my views are heard by Adobe, just adhere to the following instructions. Never use the Export function, always use the Render Queue. You can send your composition to the Render Queue by hitting control+M or Composition>Make Movie. From there you will select the blue letters that say Lossless and then choose your Output Module. Make sure you check Audio Output if you need audio encoded with it. Lastly choose your Output File Path and file name, and hit the pretty button that says RENDER.

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  How to render with an alpha channel and pull video with a black matte

  The first part of this topic is pretty simple. Whatever Output Module that you decide to render out with, make sure that instead of the default RGB setting next to Channels in Video Output make sure you change it in the drop down menu to RGB+Alpha. That will make sure that your rendered video encodes takes the transparency and renders it transparent instead of rendering it a flat black. As for "knocking out" the black in a video such as a clip of a muzzleflash or an explosion, you can either set your Blend Mode to Screen or you can use Knoll Unmult, a free plugin.

  Download Knoll Unmult

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  Why is my RAM preview so short?

  Your RAM preview area is determined by a few things. One, the length of your timeline's work area. And two, by how much RAM you actually have available to RAM preview with. In 32 bit operating systems, the computer and After Effects both can only use up to 3.5GB to 4GB of RAM per processor (however some of this ram needs to be shared for other things besides the RAM preview, which is why rendering from the command line can sometimes render something that fails in the GUI). So depending on how large your sources are, the RAM preview length will vary. Starting with CS3 After Effects added a multi-processing option which gets past this limit by launching many processes at once, each able to use up to 4GB per core. This means that if you have a machine with 32GB of RAM you probably want to turn Multi-Processing on (however, make sure you have at least 2GB per processor to use this feature successfully). Unfortunately, it still sends one frame per processor so if 1 frame takes more than 3.5-4GB to render you are likely to run into the dreaded "Frame Buffer" error. Check out the linked article from John Nack (Photoshop's product manager) & Michael Coleman (After Effect's product manager) on Adobe's roadmap for 64-bit native applications and how After Effects works as a hybrid today.

  Read Article on 64-bit Adobe app performance

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  OpenGL Issues and Fast Previews

  A lot of people ask about what OpenGL is, and why they end up getting error messages from it. Personally, I just turn OpenGL off in my Edit>Preferences under the Preview tab if I get an error message. You can also control this with the button at the bottom of the comp called Fast Previews. It has options for Wireframe, Adaptive Resolution - OpenGL Off, OpenGL - Interactive, or OpenGL - Always On. OpenGL was created to improve render speeds and RAM previews, but does a poor job if you have different pixel aspect ratios, shadows, wierd dimensions in the comp, and a number of other things. I have found that working with Adaptive Resolution exclusively saves more of a headache, and provides less failed renders and/or error messages.

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  Draft3D and Live Update

  Are your depth of field effects not showing up? Do your shadows not cast? Chances are you have Draft3D checked. Draft3D was made to disable lights, shadows and depth-of-field blurs without have to find the layers or effects and turn them off for faster RAM previews. Since they take so much time to RAM preview, you can just check the Draft3D button, so you can preview without all the other effects taking up a ton of time. Live Update is checked on by default, but sometimes users turn it off by accident and freak out when they can't see their layers when they move them around. No need to fear, just check Live Update on again, and you will be back to the way things were preview-filled and peaceful. Note: In the picture, the Draft3D icon is to the right of the Live Update button.

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  Spacial Interpolation on Keyframes, or the Boomerang Effect

  You have probably ran into this problem before, where you want your layer to move on a certain path, but for some reason it has an unexplainable movement. You, my friend are a victim of incorrect Spatial Interpolation! By default After Effects tries to smooth out your movement with position keyframes so it creates a "bend" in the path you are moving, the same kind of "bend" you see when you create a mask where the previous point had a curve, so the next point will have a curve. Well you can go zoom way far in and manually fix it, or you can right click your keyframe, choose Keyframe Interpolation, and change the Spatial Interpolation to Linear. Viola! Your annoying Boomerang Effect is gone. Check out Nick Campbell's video on this as well over at GreyScaleGorilla.com.

  AE Mistakes - Wobbly Keyframes @ GreyScaleGorilla.com

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  How Live Photoshop 3D works

  New in After Effects CS4 you can import 3D objects wrapped in a .psd file. How does this work? Well, first off you need Photoshop CS3 or CS4 Extended. Then you can take your object, exported as .u3d, .3ds, .obj, .kmz, or Collada file formats, and import that into Photoshop. When you save your .psd file, make sure that you have Live Photoshop 3D checked. Now you can import that .psd into After Effects as a Composition with Live Photoshop 3D checked on. If you open the composition, there will be a camera, an image layer and a Null Controller layer. Don't delete any of these. Use the Null controller layer to move your 3D object around, and check it out... you now have 3D objects within After Effects. Of course if you want to paint onto the object, shade it, or anthing like that, you will have to do it either in your 3D application, or you can use Photoshop's limited tools.