Avogadro 2 is a chemical editor and visualization application, it is also a set
of reusable software libraries written in C++ using principles of modularity for
maximum reuse. The development of the first generation Avogadro application and
library is documented in our paper, and this remains the preferred method of
citation at present. The motivation for rewriting Avogadro, along with
improvements and changes made in Avogadro 2 are summarized in our Source
article. We provide a set of permissively licensed, open source, cross platform
software components in the Avogadro 2 libraries, along with an end-user
application with full source code, and binaries.

The library features updated and improved rendering, where we built upon the
abstraction provided by previous API, but implemented a simple scene graph. This
makes use of features such as impostor sphere rendering, resulting in
significant rendering speed improvements while improving the quality of the
visualization. The core is built for scalability, looking to enable the analysis
of larger chemical structures and simulations being produced by computational
chemistry codes today. Emphasis has also been placed on making it even easier to
extend, using simple Python scripts to add simulation input capabilities, and
data input/output along with access to full-blown C++ plugin APIs where more
control is required.

WWW: https://www.openchemistry.org/projects/avogadro2/