FOSS gamedev and creative worlds

a simple question: is possible now only with lua?

an example: i want to create steps or slabs -I know that someone already did this-, or more complicated things such as fences... (I know there are already fences, but its just an example)

No, it is currently not possible. I had to change the C++ to make stairs and slabs, but once I get around to finishing it, it will allow you to define a list of to-be-drawn axis-aligned boxes yourself, so it is a more generic solution than just adding drawtypes for stairs and slab.

oh, i see, thanks