There is a huge variety of render farms available online, most of which support Blender. However these can be expensive and so I’m going to share with you a technique I use to greatly speed up my renders for free. We’ll be using Blender with Dropbox to combine rendering power from all your computers, though you can also use this technique on a single machine to allow simultaneous GPU and CPU rendering!
The technique is based on pointing two instances of blender at the same Dropbox folder, with “overwrite” off and “placeholders” enabled:
Placeholders create the image file before the render is complete, reserving that file name. So if one computer is working on frame 50, a second will simply jump to 51 so as not to overwrite it! A very simple but effective method.
It’s particularly easy to set up if you configure your blend file correctly and place it in Dropbox, with a relative file path for the output. This will make adding new computers to your farm as easy as opening the file and hitting “render animation”.
A Few Important Points
It’s worth noting that this only works with animations; you can split frames between machines, but to split up individual frames requires sophisticated software. Also, ensure that the sample count is high enough that each frame takes around a minute or more to render. If each frame renders too quickly, frames might be created more quickly than the Dropbox is able to update and the result will be frames rendered by more than one computer, wasting time.
Since first publishing this post, I discovered Sheep It! which is a great online render farm that’s completely free of charge. It is great as long as your file is under the size limit, and you have enough credits. It works through distributing the rendering among its members, and credits are earned by rendering other people’s work.
Here is an example of a video rendered with my ASUS laptop and a MacBook Pro at the same time, using my technique. Render time was almost halved: