Fusion effects leaves Resolve unable to read project file

Hello,

I've been running into an issue repeatedly when using Fusion effects in the edit page. Occasionally, when using several Fusion effects, my project can no longer be loaded.

I tried to find a more specific cause through trial and error, but I wasn't able to replicate the issue in any of my attempts. Each time I've encountered it, I have been using several Fusion effects in conjunction with each other (or the same Fusion effect several times).

The last two times it has occurred, these Fusion effects have been within a compound clip. I don't know if this is relevant or coincidence, since I am more likely to be using compound clips when combining several elements each with applied Fusion effects.

When I try to load the project, it gets to 100% and then nothing happens from there. It remains at loading 100% indefinitely. So far, I've only been able to recover projects from incremental backups and this usually means quite a bit of progress lost.

The Fusion effect which caused it only moments ago. As you can see, it is nothing extravagant or demanding:



I have also experienced this issue using other simple Fusion effects.

This is my Resolve log from when it failed to load the project: https://pastebin.com/raw/K1VNUSVF

And this is the only error I could find relating to the Fusion effect applied: https://pastebin.com/raw/mfmFvkDF

I'm running 18.6.5 build 7 on Windows 10. I experienced this issue as early as October last year whilst running a different version of Resolve.

If anyone can provide any guidance/solutions, it would be greatly appreciated. Fusion effects are one of the primary reasons I moved to Resolve and I am now petrified of using them for fear of losing hours of progress.

Edit:

I've just discovered that I am able to open the original project file if I first load a functional backup. If I then save it again, it can be opened without issue.

Instead of using Compound Clips, try using multiple MediaIn nodes on the Fusion page.

Instead of using Compound Clips, try using multiple MediaIn nodes on the Fusion page.

To clarify, the compound clip contained several elements - each with a Fusion effect applied individually. I was not using a Fusion effect on a compound clip.

Understood. Still...avoid the Compound.

Understood. Still...avoid the Compound.

I find them to be extremely useful and constantly use them, doing without would be tricky. Can you elaborate on why they should be avoided?

I think Jim means something like, instead of multiple nested compounds make one compound with all the videos in it and then Fusion everything with multiple MediaIns and a single MediaOut.

Personally, I try and avoid all of these as they limit the ability to edit the timing on the Fusion parts easily. You have to jump into a compound and redo timing again if you've slipped something in the main timeline.

The most stable workflow I've found is:
Use a stand in image file as your placeholder for any Fusion work. Add it to the timeline where you need an Fu Comp.
Go into Fusion and use the MediaIn node to add in any files you need from the media bin. Use the in and out or the keyframe editor to trim, slip and slide your Media.
Add a MediaOut at the end of the flow back to your timeline.

You can't nest multiple fu comps into each other like you would Pre Comp things in After Effects. It's the nature of the GPU based editing. You're better off making one Fu and putting that on the main timeline.

I think this is what's going on. The order of operations isn't the greatest in Resolve so it's not ordering the cache renders to be used inside the next top layer.
People have an issue with this in editing too. If you nest a sequence, there's a good chance you'll get rendering errors on the timeline.

If you do get errors on the render out of Fu, delete the MediaOut node and add a new one. It will force a regeneration on the timeline.

You can't nest multiple fu comps into each other like you would Pre Comp things in After Effects. It's the nature of the GPU based editing. You're better off making one Fu and putting that on the main timeline.

I think this is what's going on. The order of operations isn't the greatest in Resolve so it's not ordering the cache renders to be used inside the next top layer.
People have an issue with this in editing too. If you nest a sequence, there's a good chance you'll get rendering errors on the timeline.

If you do get errors on the render out of Fu, delete the MediaOut node and add a new one. It will force a regeneration on the timeline.

Thank you for the detailed explanation + both for the advice.

I had no idea there was a meaningful distinction between compound clips and nesting/pre-comping. I'm going to have to re-think a lot of my workflow with this in mind. Much of the work I'm doing involves animating numerous overlayed images individually - getting this done without pre-comping (or pre-rendering, for the sake of flexibility) might be tough.

I suppose I will be spending more time in the Fusion tab!

Strangely, I've found that I can open the unloadable projects if I first load a functional backup. If I then save, I am then able to load the previously unloadable version - very odd.

Yeah, there's a whole thing in Resolve that is an issue with using the GPU on a continual basis vs generating a frame and throwing it into a disk cache. This would solve multiple issues and allow the flattened sequence to be nested and have the stability that After Effects has. But it don't so you can't:/

I actually come from an Adobe centric workflow and refuse to completely slow down my pace by adhering to the Resolve way of doing things. Which is to say work slower and with more hiccups. I actually use nested sequences all the time. You have two options:

The first is to use a Saver and then a Loader in the reFusion Page before your MediaOut node. Save out your fu comp to a image sequence then load it directly back in and connect it the the out. If you do that, the only lifting that the timeline has to do is convert the image sequence into the proxy/cache format you told it to use for the sequence. Like an Avid HQX or whatever it's called.

The other option is to do a "Render in Place" on the fu comp. It's a weird patch fix to the issue of caches not playing back in real time when having too much going on between Fusion and Color. It does the same thing as the cache(?) but flattens the video and it then no longer needs any GPU to work. It's... Fine, but is a last resort because of years of years of software loosing dynamic links like it keeps back to your original fu comp. Plus if you want to change the fu comp you have tell it to go back to the orginal start the whole thing all over again. In a better world the cache would do all of this automatically and not require the extra steps.

You should definitely get used to Fusion. There is another thread where I go on a little bit about some of the hiccups but overall, you can do so much that it makes the whole program a different beast if you can work it. The edit page laughable for fx once you know what to do.

Good luck.

Oh, I meant to mention that you should look through your logs and see if you can find an error that looks like a "Fusion Dirty API call" that's the error loop that stops the program from responding. Use the Help menu and produce the log zip file and post it here. I can look through it to find what might be happening. If you can load another project and disable the the caching using "Ctrl-D", when you load the next project it will not go into the loop right away as it loads the caches in the background on start up. It's something to do with the MediaIn node. They need to write more catches for error handling into the node. At this point I can make it freak out reliably by making it use the background function. If I want to make reFusion rock solid, I have to load in the MediaIn, do the Saver/Loader trick and then disable the MediaIn till something changes forcing me to use it again. Yeah, it sucks but isn't always needed until way deep into huge projects.

Thanks Ben for all this interesting fusion info and lore on what’s going on.

Chiming in just to say that this isn’t causing a corrupt project. The project is fine but Resolve is getting stuck reading it. I suggest changing the post title as this is something that might be helpful to the devs in fixing the issue and I sure hope they read it.

I think Jim means something like...

No, what I mean is don't use Compound Clips. At all. Anywhere.

There are some current issues with Compound Clips and Nested Timelines that make them problematic at times. If you're using one and it's all good, hurrah!

But things are NOT all good here, so...take them out of the loop. Get rid of 'em. Totally.

I don't know that will help. But it's something to try.

Interesting... Jim, what have you seen with the compound clips? Nesting has always been a roll of the dice but I've never had something go sideways with a compound. Granted, I didn't use them all the time but they definitely are scattered in different projects.

I don't recall specifics as I don't use them myself. But the forums have several folks reporting issues when using them. That's why I think it would be worth building the timeline without them. See if that fares any better.

If it doesn't, then we know to look elsewhere.

Thanks Ben for all this interesting fusion info and lore on what’s going on.

Chiming in just to say that this isn’t causing a corrupt project. The project is fine but Resolve is getting stuck reading it. I suggest changing the post title as this is something that might be helpful to the devs in fixing the issue and I sure hope they read it.

Updated accordingly!

Thanks all for the discussion and insight.