How to make one-way collision?

I have a cube that has a forcefield with negative strenght (it attracts stuff) and a liquid.

I want the liquid to be able to pass through when entering the cube but when it tries to leave it I want the cube to function as collision. Put simply, the effect I want to achieve is: the water gets sucked into the cube and can’t get out. How do I do this? Maybe there is some way with normals and stuff or something else. Any help is greatly appreciated.

1 Like