Wow, this is a late reply.
Here's the technologies I know that are available at the moment for it.
ESPVision (via Vectorworks/3DS Max): (However camera inputs are broken at the moment which is how I arrived here at this thread--I do expect they will fix it in a reasonable amount of time).
Capture: (I have not used this for video in recent history but theoretically it works)
And there are a horde of other options. I'm not a huge fan of Watchout due to their licensing scheme with the dongles--you need two to have output ~ $6000--but it technically has previsualization and it is significantly more affordable than anything from D3.
Frankly, you can do a lot with QLab (Mac only) which is my "daily driver" for most small projection gigs. You can just route that as a Syphon output and "view it" as a texture.
You also might want to keep an eye out on TouchDesigner and VVVV modules if you have programming experience.
However, due to the limitations in most of this software I tend to work off a model and a cheap 480p LED projector. (I design lighting and video for theater, hence my workflow tends to lean towards models)
Hopefully this helps someone!
EDIT April 2018
Apparently this did help someone:
I've been using Capture for the past year and it is a fairly solid 3D previz tool if you are willing to use NDI or a series of capture cards. Right now it is my preference for usability/workflow.
You might also check out Light Converse
Or for PC, Realizzer
There's a few others by some major brands, Martin has Martin Show Designer and GrandMA's previz can theoretically work.