user3908: D3 Technologies offers both a previz and a playout platform for video presentations. I'm interested only in the software part, for pre-visualization of complex, multi-screen presentations. 
Using their software you can import or construct a 3D model of a stage or venue, including display screens, and apply your video elements to the screens. You then use a virtual camera to view the set interactively to evaluate sight lines, projector and lighting placements, etc.
Is there any other software that is generally used for the same thing, like maybe MESH or FrameForge?

user17916: 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). 
http://www.espvision.com/
Capture: (I have not used this for video in recent history but theoretically it works)
https://www.capturesweden.com/Products/Software
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
http://lightconverse.com/
Or for PC, Realizzer
http://www.realizzer.com/
There's a few others by some major brands, Martin has Martin Show Designer and GrandMA's previz can theoretically work.

3908: <p><a href="http://www.d3technologies.com/" rel="nofollow">D3 Technologies</a> offers both a previz and a playout platform for video presentations. I'm interested only in the software part, for pre-visualization of complex, multi-screen presentations. </p>

<p>Using their software you can import or construct a 3D model of a stage or venue, including display screens, and apply your video elements to the screens. You then use a virtual camera to view the set interactively to evaluate sight lines, projector and lighting placements, etc.</p>

<p>Is there any other software that is generally used for the same thing, like maybe MESH or FrameForge?</p>
 17916: <p>Wow, this is a late reply.</p>

<p>Here's the technologies I know that are available at the moment for it.</p>

<p>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). </p>

<p><a href="http://www.espvision.com/" rel="nofollow noreferrer">http://www.espvision.com/</a></p>

<p>Capture: (I have not used this for video in recent history but theoretically it works)</p>

<p><a href="https://www.capturesweden.com/Products/Software" rel="nofollow noreferrer">https://www.capturesweden.com/Products/Software</a></p>

<p>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. </p>

<p>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. </p>

<p>You also might want to keep an eye out on TouchDesigner and VVVV modules if you have programming experience. </p>

<p>However, due to the limitations in most of this software I tend to work off a model and a cheap 480p LED projector. <em>(I design lighting and video for theater, hence my workflow tends to lean towards models)</em></p>

<p>Hopefully this helps someone!</p>

<p><strong>EDIT April 2018</strong>
Apparently this did help someone:</p>

<p>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. </p>

<p>You might also check out Light Converse
<a href="http://lightconverse.com/" rel="nofollow noreferrer">http://lightconverse.com/</a></p>

<p>Or for PC, Realizzer
<a href="http://www.realizzer.com/" rel="nofollow noreferrer">http://www.realizzer.com/</a></p>

<p>There's a few others by some major brands, Martin has Martin Show Designer and GrandMA's previz can theoretically work.</p>
