Blackmagic Forum

Hi guys,

First post, first question I'm kinda new to the Video Compositing Software, especially advanced ones like Fusion, and I have just finished my 360 VR video and I try to render it. But at some point, the rendering stoped (after 6h or so ) and apparently the only error that is shared by multiple error (I guess it always starts with the Loader) is: Too many open files. It causes the rest of the group to turn off like a domino effect

Can anybody help me with that

Best regards

check your loaders at the frame that doesnt render,
can u post the console log of the error ?

I'd contacted with Apple Support because the same error occurred in the other app so I figured it's a system problem, and I was probably right, but still not sure what caused it

So I had only 50gb space left on my SSD, and as a support team suggested, I should free some space and it will solve the problem. I did so and the error did not reoccurred.

But the question is, why is that a thing?

INB4: I had enough room for a video itself.

All right, so after freeing some space, I've tried to render my project and and same error occurred.

The log looks like this:


Any ideas?

Seems indeed a system problem. I am a PC user but maybe there's a way to increase the number of open file handles in your SO. An environment variable for example.

In the meantime you could turn "Simultaneous branching" off in Preferences>Memory. And you can lower the number of frames rendered at once.

This can lower the number of files open at the same time.

What does that simultaneous branching changes?

"simultaneous branching" means that different cpu cores can render different branches of the flow.

lets say you have a merge with a some nodes for the BG and some for the FG. then fusion can render the FG and the BG simultaneous with different CPU cores.

if you turn it of then you have to wait for each branch to be calculated until the next one is started

"frames at once" means that fusion tries to render different frames at the same time with different CPU cores. so it will calculate frame 1,2,3,4,... simultaneous instead of one after one


is see a replicated3d node in your console message with some strange frame times. how many duplicates do you have in the replicate3d? and why do you have that fraction of a frame in there (offset?)

It's because of that:


but I don't know how to fix it. Every node in my comp starts at 00:00 (checked it on the timeline).

Replicate3D2 replicates slowed down video put on the 3D image plane and locates them on the points created with particle system.

As i just have noticed, simultaneous branching was already off and it was rendering 2 frames at once so I guess that's not the point

On Mac there is set maximum files that can be open both by User and System (separate values) and I have already increased that number from 268 to over 64000 as I recall

If you are using a Time Stretcher and your keyframes are not linear (i.e. smooth), be sure to adjust the spline handles in a way that do not lead to negative time values.

Maybe this is leading to your Replicate3D errors.

I'm using TimeSpeed, not TimeStretcher.

This is the branch that's causing the trouble:

at time -0.xx ! is the problem.
Maybe u are using some particle effects , with a "preroll" .
Extend your comp global start time to f.E. "-10" , and i guess, this will fix it.