Downloading Actin 2.0 from our website was free. The actual developer of the software is Energid Technologies Corporation. The software lies within Education Tools, more precisely Science Tools.
From the developer:
Actin coordinates motion of the joints and base for one or more robots. A developer just gives desired tool motion through a simple language, and Actin produces real-time algorithms for setting motor positions and rates. Actin works with almost any joint type or tool type and with an unlimited number of degrees of freedom and branching connections.
You may want to check out more software, such as Actinic, which might be related to Actin.