Hi,

 

I want to create a non-full block that has to be placed under water.

If I use a custom rendered block (like fences), it will fill the remaining block space with air instead of water.

Now I want the empty block space to be filled with water instead of air.

Is this possible and how do I signal minecraft to fill the empty block space with water?

If this isn't possible, what is the best way to mimic the effect of water in the block?

 

Thanks.

Can you explain a bit more what you mean?

You could use water material, render will be done by the game. However, that would mean you should add "Level" blockstate (like fluids) to avoid crashing the game.

This method work and is easy to implements however there are some render glitch near non-opaque blocks (expect water), glass for instance.

 

Or as diesieben07 said, you could create a block model, but it's more difficult I think. (For side rendering)