Has anyone looked into using a short-throw on the floor with rear projection?
I'm not sure what sort of size that would end up at, but it would remove all of the issues relating to shadows and ceiling mounts.
I did.
*** Lengthy Rebuttal for Clarity**
Through several different attempts with a Viewsonic PJD2121.
General Info>
- Veiwsonic list the throw at 28" ...3' more accurate. and at the shortest throw distance produces a 45" diagonal basically a 27"x36" rectangle display if utilizing a default(4:3). Though this particular projector does have "letter box", some do not, so will use "normal" mode for this purpose of discussion.
My goal was to be able to sit 10 people (including DM) around the table. So this comes into consideration on my analysis.
Lastly, the projection when reflected can change size based on where the reflective surface is in relation to the projector, I will discuss as if this distance is basically equal. AND if equal, your reflective surface sizing will have to increase based on how large you wish the final projection to be.
Also, any reflection is good for maps bad for text.
Attempt #1>
Direct projection from undertable.
This requires some sort of screen surface to "capture" the projection. Two possibilities are a parabolic lens (cannibalized from an old projection TV), or the use of vellum paper. The use of the lens produced a nostalgic "rainbow hue" often found on the TVs of the 70s using this "tech". The vellum paper has to be supported, so I sandwiched it between two pieces of glass (in this case an old sliding patio door).
While I preferred the softer tones of the vellum, you loose abit on sharpness. The real downside was even with a short throw projection, the table had to be nearly 4' off the floor.
Attempt #2>
Reflection undertable.
- Depending on the degree of keystone you can play with this abit, but again for this purpose, we will assume keystone is set to zero. As Jamz points out, you do loose leg room undertable and for better projection the projection field should be boxed in to save moving it, and lost light. Problem with boxing is this elevates the heat which projectors create a lot of leaving you two choices, vent the heat out or overheat your projector. While reflection will lower your table height down by roughly halve, it doesn't change the finished projection size, currently still 45" diagonal. However, the table doesn't have to be two feet tall either, so raising the table back to say 36" gains a foot of projection area on the "Throw". So at a throw distance of 4' I get a projection of 60" diagonal 48"x36". Not bad, but at those lengths, I might only be able to seat 6 around it, not 10.
Attempt #3>
- Similar to Attempt #2, but played with the 16:9 (letterbox) projection. This approach still only gave me the same seating, but abit more comfortably (30" per person was the goal). The projection diagonal staying constant gave me a display size of about 53"x30" or put another way a table 5'6" x 3' with a 6" space around the edge for books, dice etc. Not bad, but again still too small for 10 people.
The various attempts all were considered fail.
So, I went with above table projection, only to find I couldn't see finer detail on some maps due to lights being on in the room during game play. All projection is effected by the amount of ambient light in the room vs the amount of contrast and lumen they produce. It varies from projector to projector and personal taste.
After several game sessions we abandoned the projector for the embedded TVs (as noted in my earlier posts). The end result (currently hehe) is a table 11'x3'6" with a display surface of 24"x84". At first I thought the 2' wide display would be too narrow, but after several months I have found it works well because it leaves 9" on either side of the screen for books and dice trays, etc. and I can scroll the maps used quite easily.
A comparable projection application would have required the throw length to be 7' (thus making table heights difficult) and 5'6" wide (which my game room would not comfortably support) and still not address lighting issues or text displayed if mirrored.
Some helpful links in reference to this
http://www.projectorcentral.com/ViewSonic-PJD2121-projection-calculator.htm
http://www1.viewsonic.com/products/archive/pjd2121.htm
D20Pro's partnership with Mesa Mundi see a lot of possibilities for the table top gamer... So I am considering this>
http://mesamundi.com/collections/multitouch-overlays/products/pq-labs-g4-touch-overlay-84 This as others have noted is about the cost of a low end 4k TV but would give you touch capability.
And as a D20pro user / developer, I was hopeful of the RW partnership as well, but frankly, RW just struggles to deliver on their own target goals, so you can't tie too many "hopes" on what they do.
I hope you find this helpful
DLG
