After Effects timesaving: Rendering
Basic Render Tips
There are many ways to set up a composition that can inprove render times dramatically, here are a few:
Motion blur - If you turn off motion blur for a preview it can more than half your overall render times. You can switch this off either with the motion blur switch in your composition (for RAM previews only) or in the Render settings window.
Turn off live preview - You can also speed up the render slightly by hitting Caps Lock before you hit 'render' and move your render queue tab to the same window as your composition workspace. This means that whenever you are rendering, after effects isn't using extra processing power to show the individual frames as they are completed.
Render Settings - If you are outputting a preview, it might be a good idea to open the Render Settings and reduce the quality to half or even a quarter if working in HD.
Multiprocessing - Multiprocessing is useful, but only really worth using if your machine has enough RAM to allocate a good amount to each processor. When using After Effects CS4+ on a 64 bit operating system, it launches multiple instaces of the program in the background - one for each core. When setting the amount of RAM allocated to each core you must ensure each one has at least 3GB, and there is additional RAM left over for the operating system and other programs to use, otherwise the system will grind to a halt.
Proxies - A proxy is a placeholder file that acts as a lo-res version of what will be in your final output. Perhaps you have a render-heavy background or large footage or images that don't need to be full-res until the final render. You can render a lower resolution precomp and use it as a proxy by right-clicking on an item in the project window, going to Set Proxy/File... and navigate to your file. A grey box will appear next to the item that you can use to turn the proxy on or off. Proxies are ignored on a full render, but you can change the proxy settings in the Render Settings
If you work with huge images, especially .tif files, after effects will struggle to read them, so as a standard practice I will always convert my images to 72 dpi and resize so the resolution is the maximum that I will need to display, no more than that. Photoshop has a handy script built in where you can resize and reformat images in a batch, this can save a lot of time.
If you are using a plugin such as Particular or Form, ensure that the particles are only visible where you need them. Even if particles are behind the camera or obscured by another layer, they are still rendered and add time to the process. Try to keep generated particles where you need them, and make sure that you trim all plugin layers when you don't need them.
Background Rendering Software
If you just have access to one machine, a lot of people use the excellent BGRenderer to output precomps and small renders whilst they carry on working. This is effective but for a free option, Adobe CS5 onwards comes with Adobe Media Encoder. On the face of it Media Encoder just looks like standard conversion software, and although it is very efficient for this use, you can also import unrendered After Effects compositions for it to output.
To import an AE composition, open Adobe Media Encoder and select File/Add After Effects Composition. Browse to your After Effects project and wait for a link to be established. The items in the projects composition panel are then displayed on the right, browse to the comp that you wish to render and click OK.
Check the render output settings and importantly, the trim area (sometimes this isn't preserved from AE) and hit Start Queue.
There are restrictions on how you can render files using Media Encoder. As far as I know there is no option to render with motion blur (perhaps a blessing in disguise?), no multimachine preferences with an option to skip existing files, no option to output with an alpha channel and from experience it seems to render a little slower than AE as it displays every frame as it is rendered - a feature that can add time to a render and can be avoided in After Effects. These disadvantages mean that at the moment BG Renderer is probably still the superior of the two but Adobe Media Encoder can still be very useful in a pinch.
For more help with rendering options, there is a guide on the Adobe Help site.
An option to speed up those long renders is to use a multimachine render, or a small homemade render farm for the bigger jobs. As long as all of the machines have the same software, fonts and plugin versions installed you can save a lot of waiting around by setting them off on multiple machines.
Once you have your comp ready to render with the work area trimmed and put into the render queue, set up the Output Module to render as an image sequence (.png, .jpg or .tiff). I would suggest, .png as it supports alpha channels and produces smaller files that retain their quality. Create a folder for these to go into and open the Render Settings and select the 'Skip existing files' checkbox - this will ensure that no machine has to render the same frame twice. If another one is working on the same frame it will go onto the next.
This is a technique best saved for renders that will take longer than a few hours usually, as once you have then image sequence you will of course have to output that into your preferred video format along with sound which could take an hour in itself once the main render is finished but you can easily output this in Adobe Media Encoder or BG Renderer.
Thanks to Aaron Scott for the multi-machine render advice.
Posted: Tue 27th Mar 2012
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