A Question Related to Paper2D Material ^_^

Hello everyone!

First of all I must say I am completely newbie when it comes to material editor. So even a little step on how to achieve what I need is mostly appreciated!

Here is a small demonstration;

I want you to imagine this; blue is sky and black is the ground. Sky and Ground is One Sprite combined and they are behind the character, which is the White Box.

Normally if I lower Character Sprite down, you would still the character completely, as there is no ground beneath. It’s just a sprite at backside!

Now here is what I need to achieve;

Here you see the character is slightly below from where it was before. And despite the fact that there is no ground beneath, it looks like he went inside! We know that the ground’s Z location is -94. So what I need is this:

I need a material that is aware of the world position, and don’t let itself render below that -94 point, to make it look like the character went below.

Thank you for your time!

PS: I can’t seperate the sky and ground sprites. The situation is abit more complicated than what I described so its out of question. I could also make another ground sprite that is in very front, but I dont think thats proffessional. So I would like to fix it with material itself! Thanks!