3D Projection mapping for a stage set

This question is not vvvv-specific but I hope that someone on this forum can help me!

I’m part of a team that is trying to do 3D video projection as a stage set design for a teen summer camp. I’m in the process of testing and matching my 3D camera (using 3ds max) to the actual projector. Does anyone have any advice for how to best match my 3d camera to the actual projector?

The projector is an Eiki LC-XB26.
http://www.eiki.com/Products/LC-XB26/Specifications.aspx

I know I’ve got to be missing something because I’ve got the stage pieces at the same size and coordinate position as their 3d counterparts but the actual projection is way off. Any suggestions would be greatly appreciated!

Thanks!
Phil

test it with digital camera…

I could probably come up with a temporary solution by using a digital camera (if I correctly understand what you mean by using one) but I’d like to find another solution. I’m currently using a small projector with a scale set in inches for testing. The actual set will be much larger (in feet) and has not been built yet. I won’t have access to it or the 10,000 lumen projector until a week before the camp. So I need to create my animations and render them out between now and then. I hope that makes sense. Thank you for the reply!

well if you solve your small projector you will solve the big one no problem
it’s just a matter of ratio

I’m sorry I don’t understand how to test with a digital camera. Wouldn’t it need to have the same settings as the projector, which is what I’m trying to do witha a virtual camera?

Thanks!

hi BamaBleach

I am not deep into 3DsMax but I don’t think that the camera there has lens shift.

take a look at the projector node in vvvv, that can successfully be adjusted to match the real projector, just make sure you know what all the parameters do in it and that you fill them.

sogukoGENKI and catweasel made a workshop at node10 about projection mapping, I don’t know if there are any patches available from there.

another good resource is here: how to project on 3d geometry

I hope it helps

-sunep

Blender s got Camera shifting

You need to change the Zoom Ratio(or Image width on lens, near, far), it’s inside the Projector node, just hover your mouse over node and right click to change all parameter. These are characteristic parameter of each projector, each projector has different characteristic, you may need to change it according to specification.

Goodluck

I think he s asking about 3ds max cause he wants to do some renders beforehands on a 3d editing program with all the nice postprocessing features you can get.
Problem is as usual that cameras have 0 shift-y while cheap/home projectors have around -0.5 or less shift-y.
That said you can either change the shift-y on the virtual camera (as I mentioned Blender can do that, dunno about max) or find a projector that you can set to shift-y = 0.
You can also do some trickery with Homography but that won t give you perfect results.
S.

Thanks for all the feedback. I’m pretty sure that Max has “y-shift” as you call it. You can place a Camera Correction modifier on a camera and it allows you to do 2 point perspective correction. I’m going to play with that modifier and see if I can get improved results.

Thanks!

i’ve made several projection mapping, and i always pre render on compositing software like AE. the output from MAX is just to get the perspective to mantain visual illusion.

if the projection media more complicated, better you test with digital camera, make a test image on photoshop-distort it if necessary, project it, make adjusment until you get the best result, and than finnaly make a composition in AE based on adjusted photoshop image.