If I render your file I get no problems with the mask being misaligned:
As for the rough edges by the armpit, those are part of the key from the green screen, they are not part of mask you are using as garbage matte.
The keying needs to be refined, so that you get better separation.
You might want to try blender.2.92 so that you don't have to convert from ...
Thanks to the help of the community, the current solution to solve the wine is using shader nodes with a map range and a texture with a glas full of wine and one without wine.
see blend file:
This is a solution, but still wondering how to create an animated mask on an image ...
Since you will have to separate lines of glass from red wine and white line on wine surface (that has to be part of animated section), seems to me easier to recreate pictogram in some vector app (so you can work with always sharp and clean shapes), import as SVG and animate with Boolean Modifier.
add the glass Solidify modifier to get ...
I didn't check a Mask option, but seems to me more natural to use an Object as a Mask and Shadow Catcher in once, so shadow follow the shape.
Alpha Over node seems to be working as expected.
Image in my 3Dviewport is an Empty object for a reference it doesn't influence a render. For the same effect (and probably easier) you can use image as ...
I think I can point you in the right direction.
You need to define a wave texture and apply it along a gradient, so we'll need a wave texture node, and if you use a separate XYZ node you should be able to find a direction that gives you the gradient you need. For this object it's the Z axis.
I'm going to use a Color Ramp to invert the Z gradient and give ...
You have opened the UV editor window
Open image editor window, shortcut Shift + F10
At around top there should be written something View(next to Image Editor button), click it and change it to Mask
You can then create a mask by clicking + New button.
I found a solution. Apparently, you can use a holdout node in the shader editor to get this desired effect.
Create a new material or use an existing material and assign it to whatever object you want to hide and hide whatever is behind it. Go to the Shader Editor and add a holdout node and assign it to surface, you can create the holdout node by going Add &...