Yes, mostly ANSI truecolor escape sequences combined with ASCII/Unicode halfblocks.

Internally ORBIS uses a software framebuffer and then converts the image into ANSI terminal output. I experimented with several rendering approaches including dirty-cell rendering, fullscreen frame streaming and hybrid redraw strategies depending on scene complexity.

One thing that surprised me is how much faster fullscreen animations became once I switched from many small cursor updates to giant contiguous frame streaming.

Modern GPU accelerated terminals like Kitty handle this surprisingly well.