Question Object Fill Shader

Hello, I'm trying to achieve a fill effect that you can control with a slider just like you can with the Image fill amount slider. It doesn't work as it should, I change the fill amount and It doesn't start from the bottom or top. I've played around with the position node too but no luck, even though I managed to get it working, the numbers were incorrect.

 

If you are using UV coordinates, most likely your setup goes wrong if your object UVs are not aligned how you want your up-down axis to be. i.e. most likely you would want to have your object unwrapped so that up is up on the screen and so on. Then when you perform a fill on y-axis (v), the object would fill up from bottom to top.