BenQ’s product-page (on their own site) doesn’t list it in the specs, but does mention it in the FAQ:
The current firmware version only supports 3D Frame Sequential (PC) and Frame Packing (Blu-ray), the side by side 3D and Top & Bottom 3D are not supported yet.
The display unit/monitor has to support side-by-side, which is the generally the oldest supported type, but nowadays the most common-supported type is the 3D Frame Sequential type, which basically each sent frame switches between the R and L eye/projector.
The framepacking method would be closest, as that generally is Left and Right (respectively) stacked on top of one another, with a few added pixels of blackspace. other then that it is simply two fullsize images on top of one another.
I’m not sure if VorpX already has a top-bottom 3d output, maybe that could be adjusted/adopted in order to get (even if somewhat finnicky) framepacking support :)