Download of Octogris 3.0.6 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac app was originally developed by GRIS-UdeM. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. Octogris for Mac relates to Audio & Video Tools.
From the developer:
OctoGRIS3 is a multichannel sound spatialization plug-in (up to 8 sources / 16 speakers) available in Audio Unit and VST formats for Mac and PC. The free and open-source plug-in allows movement of multichannel sound sources on a variable set of speakers. Modes of grouped movement and a trajectory system are provided for spatialization of stereo and multichannel sources.
You may want to check out more Mac applications, such as M-Audio Key Rig, which might be similar to Octogris.