Mega slowdown.

Hi, I have a big problem with slowdown in my scene.

I’m working in a project with only one scene, three columns in that scene and the length is under 300 frames.

My computer is pretty good, Core i7 processor, 4 gig RAM, nvidia graphics card and so on.

I’ve checked and there doesn’t seem to be anything scanning or working in the background and, other than firefox, I have nothing else open.

It was working fine one second and then just slowed right down to the point where it’s unworkable.

Any ideas what could be causing this?

Update: I’ve checked if there’s something wrong with toon boom or if it’s the file itself by opening a new file and worked it for a bit and everything was fine.

I then tried transferring the drawings from the trouble file via the library to the new file and it seems to have transferred the problem too. Instant slowdown.

What could be causing this?