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compositor is (unnecessarily?) slow
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Hi all,

The compositor seems to slow down a lot at a certain limit. In the attached
file the last nodegroup "despill" (which does not do very much) is deactivated. If it is
activated the tree is executed a lot slower (5-8 times slower!). This seems to
be a bug, as the nodegroup on its own can be executed quite quickly.

till then, David.

Event Timeline

the scene is a 4k composite. and the node group does many simple operations. this is a known issue with the new system, but would not consider this as a bug.

Okay, maybe not a bug, but there seems to be some really important optimization missing,
here are the render times on my system:

without despill node: 5.41sec
only despill node: 1.65sec
with key and despill: 41.54sec

This is MUCH slower than I would have expected, and I don't yet understand why it is so
much slower.

The reason for the slowdown is that with your setup no buffers are introduced by the system. If you add a blur node (with size 0) between the groups you will see that the system will be faster.

Perhaps we need to introduce buffers when too many simple nodes are used.

A proposal to solve this issue is being discussed with the committers

check revision 54281. Please test and report findings.
See commit message for more details.

Jeroen Bakker (jbakker) changed the task status from Unknown Status to Resolved.Feb 3 2013, 6:24 PM