How do I expand a mask in one direction?

Hello,

I have a rounded rectangle mask that I'm using for a lower third style title. I want to keyframe it to expand down (so as to accommodate more text), but the height control changes the height in both directions.

How do I expand it in one direction only? Is there a way to change the origin's position (i.e. from center to upper left in my case)?

TIA,

D.

I'm guessing the lack of answer here means it's not possible?

Literally the first effect I try to do in Fusion. Oof.

Or, we just don't know.

You may be both Lewis and Clark on this one.

You can add a Transform node after the Background node and change the pivot point to the top of the rectangle. Then when you change the y size, it will expand down.

Thanks for the suggestion Eric - I looked into it but it won't quite work for a rounded rectangle, since I don't want the corners to be scaled.

I figured if you move the center of the rectangle at the same time you're changing the size, and if they change at the same speed, you can make it look like the rectangle is growing in a single direction BUT the corner radius also changes in relation to the sides, so that doesn't work either. Maybe I'll keyframe the radius as well, but it's starting to feel like a weird hack for what I thought would be a simple effect.

In theory:

If you set the pivot below the upper corners then merge a copy of the original rect over top of the transformed one, masking that to include only the area above the pivot, that should in effect prevent the upper part of the rect from scaling.

You could then merge a copy of everything below the pivot over top of the lower area, transforming with keyframes to move that downward as the rectangle expands, to preserve the lower corners.

How well that will work may depend on how much you need to expand the rectangle...

Also, this would have been a better question to ask on the Fusion forum rather than the Resolve one.

Thank you for the help Frank. I had the idea of using several masks, but wasn't quite sure how to go about it - your solution sounds like it might work. Still a bit overwhelming for a newcomer at Fusion.

I'll post there next time - I assumed it was reserved for Fusion Studio.