Optimizing Flow - Unused nodes being evaluated

Hello, I just started using Fusion 7 for a compositing project. I've been loving it so far, and coming from Nuke it's been a breeze to learn. My biggest gripe is that when working with many passes things start to slow down fast. It seems that Fusion evaluates nodes top-to-bottom; that is to say, it doesn't check if a node is actually used downstream before evaluating it. This is usually not an issue, but when you have a Merge node that is blended to either 1.0 or 0.0 (and set to Normal blending) it only needs to evaluate the branch being shown. Calculating every branch with a valid input at every frame is a huge resource hog.

I've figured out that the trim settings on loaders can be used to mitigate this, but I am wondering if there's a way to have Fusion check node usage upstream from the saver or viewer, a la Nuke, rather than process everything with an input?

-Josh

By default, that's exactly how Fusion works. You can override that by right clicking on the button to the right of APrx and choosing which update mode you would like.

I saw the All / Some / None setting, but despite having it set to Some I've watched Fusion hang on unused branches (the nodes light up). It seems to process from each Loader out, no matter what part of the node tree I'm viewing.

This is in Fusion 7, the non-studio version.

Might have to post an example comp. It's working correctly for me.

I'll try a clean install on my home computer this weekend, if that doesn't do it I'll definitely upload an example.

Hi, just posting a follow-up, Fusion seems to be working correctly for me now. If I notice it happening again I'll make a copy of the file and share it on the forums.

For now, though, I think we can chalk this up to user error / fatigue