When 'Frame grouping' is selected in the interface, the system allocates a sequence of frames to a render node, instead of a single frame at a time. Activating this feature can significantly decrease the render time (and costs) for projects under certain circumstances. We recommend activating this option in two specific cases:
1. When the project has very short frames (under two minutes per frame).
2. When the project is very complex and has a very long load time (the stage before starting the render)
The number of frames in a group should be set depending on the render time per frame. For very fast frames (2-3 seconds per frame), the group size can be set up to 50 frames. For longer frames (up to 2 minutes per frame), we recommend a maximum of 10 frames per group. For longer projects (over 5 minutes per frame), we recommend a maximum of 3 frames per group. Setting a too large number of frames in a group can negatively impact the delivery time in case of errors or crashes at the 3D software level.
Important: We recommend running a few tests with frame grouping before launching the final render. In some Blender versions there are bugs that cause incorrect frame updates when using frame grouping (for instance motion blur being applied only to the first frame in a group, or rigs not updating correctly)