The first time an ArchiCAD material is selected from the plugin, the plugin will convert that ArchiCAD material to an Octane material. Once this happens, the Octane material should be the ‘master copy’ of that material, since changing the ArchiCAD material will not automatically change the Octane material. If you need to at any point, you can re-convert the ArchiCAD material to an Octane material by selecting ‘Re-Convert From ArchiCAD’ from the Additional Options popup.