fusion polygon mask keeps changing shape

Basically that's it.
I've animated the polygon mask to follow a camera movement so that an image passes behind the background.
I did this with key frames > shape animation one frame at a time.
This may not be the best way but I'm new to Fusion.
Having save the project and re-opened it the polygon shape has moved at each keyframe in a random way.
If this makes sense, any ideas?
Thanks

polygon-ok copy.jpg (237.39 KiB) Viewed 686 times

one frame back copy.jpg (231.15 KiB) Viewed 686 times

I am not sure what you did.
Did you change the shape one frame at a time or did you try and move the polygon's shape with the shot?
I see that you have the center animated as well as the shape itself.
So is your polygon changing shape when you don't want it to or is something else wrong?

Hi Sander de Regt
I changed the shape one frame at a time.
It is changing shape when I don't want it to.
Actually between closing the project and re-opening it.
I suspect there's an easier or more efficient way of doing this.
Any suggestions gratefully received.
Thanks
Chris

Can you share the comp with us? Just replace your MediaIn/Loader with a BG or a Fasnoise. Because I haven't experienced this myself, so I wouldn't know where to begin with giving advice.

Hey

I think I recognize this weird behavior... What you can try to troubleshoot that is to put many "major" keyframes every 5 or 6 KF (I'm not in front of it, by major I mean one option you can fin in the menu when right-clicking "for shape animation").
I don't remember the solid fix but those keyframes won't move, unlike automatic ones you get when you tweak the polygon...

Can you share the comp with us? Just replace your MediaIn/Loader with a BG or a Fasnoise. Because I haven't experienced this myself, so I wouldn't know where to begin with giving advice.

Thanks for the reply. I will of course share the comp but don’t understand your instructions. Sorry.
I have no idea what “MediaIn/Loader” or “Fasnoise” mean.
Thanks again

I will of course share the comp but don’t understand your instructions. Sorry.
I have no idea what “MediaIn/Loader” or “Fasnoise” mean.

Of course I meant 'FastNoise' which is a node. But if you don't know what a MediaIn is, then I suggest you do some training in Fusion first, because most suggestions and replies over here, will assume you have some basic knowledge of Fusion.

This is not to be mean, but it's difficult to explain the meaning of a word to someone, if they have never learned how to read to begin with.

So please try to learn a little about what you're doing, so we can help you better.

Ah!
It's not mean. It must be hard to help inexperienced users.
I have done some training.
I now realise what you mean by MediaIn but can't find what you mean
I have a Media/out node
FastNoise seems to be about audio so is not necessary (I could be wrong)

Here's a screen shot in case it helps.

My workspace

Screenshot 2024-05-02 at 11.07.23.jpg (370.66 KiB) Viewed 498 times

Hey

I think I recognize this weird behavior... What you can try to troubleshoot that is to put many "major" keyframes every 5 or 6 KF (I'm not in front of it, by major I mean one option you can fin in the menu when right-clicking "for shape animation").
I don't remember the solid fix but those keyframes won't move, unlike automatic ones you get when you tweak the polygon...

Thanks Sam
Do you mean Right click > set key?
Cheers
Chris

Yep, sorry I didn't remember it specifically. I don't mean it's a real explanation/solution for what you experienced but I surely remember it fixed that issue (no matter how and why)

Hi Sam
That seems to have fixed it.
Right click on shape animation > set Keyframe
thanks

I'm glad you resolved it, though this pseudo fix doesn't really explain where the issue comes from