LumenRT VIZ is a fully functionnal product that is Free for non commercial work. Click here for more info.
The trial version of LumenRT Architect is not available yet.
In the mean time, since functionnality is very close, you can download the free LumenRT VIZ. If you specifically want to test export from ArchiCAD, you can try that in LumenRT Studio.
The trial versions of LumenRT Studio and GeoDesign 2015 are fully functional, with the following restrictions:
A download link will be sent to the e-mail address in your e-on software account. If you don't have an account with e-on yet, you need to create one first: