I have some shot animation that was matched to a non linearly retimed plate. I want to make it linear again.

I have the curve that would otherwise transform a linear shot to the retimed shot, and I'm just struggling to figure out how to apply the curve in reverse. I have the curve in CHOPs with a chan file, but I'd give my CHOPs score a C- on a good day.

The retime curve remaps 919-1163 to 1001-1050, with a change in retime rate happening at around frame 1008.

I put together a sanity check timeshift for myself to see what the final output values *should* look like, and it looks like I should be arriving at values of 1009.3-1013.4, with the change in rate occurring at 1010.9. So… 4.1 is the range of values I'm looking for in the end.

It occurred to me that maybe I needed to base it off the slope of the curve and not the absolute values. If the retime was jumping by 5 frames for each real frame, then it makes sense that the inverse would jump by .2. Summing up the inverse values would then give me some kind of inverted curve. Unfortunately, I think I'm still a bit off the mark. Summing up all the inverse values gives me a value range of 17.7, which is obviously higher than the 4.1 target value. And that's to say nothing about getting the right offset value.

Has anyone solved this before? Or maybe someone can suggest something else I should look into?

Thanks,
Ben

Okay, I have it figured out. Short answer is that I can't easily solve it in CHOPs (or at least I can't with my limited skill with CHOPs).

My solution was basically to use CHOPs to get the initial curve, then make a python callback to grab the hou.Tracks off the chop node.I then build an animation curve from the two values, swapping the X and Y axes, and then using `chf` to look up the appropriate value.

My problem earlier is that it doesn't seem easy to swap the X and Y axes in CHOPs itself. The shuffle node creates a bunch of different tracks, which isn't really suitable for me.