Of course, when I speak about archaeological vector drawing, I mean a GIS based technique (like the one described in this old post). We already developed a little bit further this methodology in order to use it in a semi-automatic way for archaeological finds (related post 1 and 2; bibliography here), so that this post can be seen as an integration of that work-flow. For the concept of RTI, I suggest you to read +Rupert Gietl 's post about a large scale case of study for such an application and my post about the open source tool developed by Giampaolo Palma (Visual Computing Lab of the CNR-ISTI).
The concept of RTI-like raster series is pretty simple: if in a common archaeological excavation is planned an RTI documentation (e.g. to further analyse particular artefacts such as small pottery fragments, coins, inscriptions in stone, etc...), than it is also possible to use some of the original pictures (with different light conditions) to simulate an RTI viewer within any GIS software. Once one of this picture has been rectified (and georeferenced, when needed), the related worldfile can be used also for all the other images (considering that they have all the same size), so that in QGIS it is pretty simple to create a raster series through the Time Manager plugin.
The video below shows the result of this operation on a pottery fragment from the excavation of Khovle Gora, an archaeological mission in Georgia which we supported for the University of Innsbruck (Institut für Alte Geschichte und Altorientalistik).
I hope this post will be useful, have a nice evening!