Invisible areas under custom blocks, how to remove? [Solved]

[Frostyhobo47]

how do you make it so that there aren't invisible areas under a custom block like here

[Cryptic]

I reccomend making the model bigger, because its smaller than a normal block

[Sphax]

Only "transparent" blocks can have any kind of 3D model.
Solid blocks can't have a see-through 3D model.

Example:
Logs are solid block
Stairs are transparent blocks