camera settings for projector

[Lennart Wåhlin]

Looking at the specs of the projector we have:
DLT width 18mm, height should be 13.5 (4:3 ratio).
That gives an aperture of 22.5. (Your 2.5 might be a typo?).
(Aperture and focal length is always in mm.)

The “digital” equivalent of the focal length 28.4 (35mm camera) is 14.75.

You can use a dof calculator to check this, and I even made
a free one for Cinema that you’ll find at:

http://www.tcastudios.com -> xfiles -> SteadyTOOLS.

Hope this can help a bit and I’m not missing you intention.

Cheers
Lennart

aka tcastudios

[Nathan Byrne]

Hey Lennart,

Thanks so much for this, I really appreciate it. I’m going to try to nail it over the weekend.

Nathan

[Nathan Byrne]

Hi Lennart,

I must be missing something. I dropped the SteadyTOOLSPlugins_R10 folder in the Plugins folder, but C4D will not recognize the plug ins.

Any thoughts of where I’m going wrong? I’m VERY new to C4D.

Thanks,

Nathan

[Lennart Wåhlin]

Please check the install instructions.

“Load SteadyDOF and SteadyQTVRv2 from the “SteadyTOOLSObjects” folder”

That is, they load into the document as objects with their expressions attached.

Cheers
Lennart

aka tcastudios

[Nathan Byrne]

Thanks so much for that. I did manage to install the Object user preset Steady_DOF_R10, and there are a great amount of controls that this allows. Did you design this (if so, I’m in awe).

However, I’m officially overwhelmed.

My intention is to create a scene in C4D (wall’s and geometric shapes), create a camera, place it in the scene and render it out at 1024×768. Play it back through a projector and have it line up with the real world wall and geometric shapes.

Here is a link to a very simple project and the specifications for the Optima 738 projector. If there is any chance anyone might be interested in telling me how this can be accomplished, I would be SO greatful.

https://download.yousendit.com/TTZseFVhZy83bUJjR0E9PQ

Thanks.

[Lennart Wåhlin]

I can’t say I see much of a problem here
Model your stuff at scale, place the camera in the scene
corresponding to where you will put your projector in real life.
(Thou try to have it placed horizontally)

In SteadyDOF type in the values from earlier post of mine
(I used the same tech info as you provided in the dload.)

Have your render output set to 1024×576.
The result is as good as it could get.
You will still have to fine adjust the projectors zoom
and keystone in the end.

Have in mind that the Cinema camera is a “pinhole” camera,
it has no physical lens artifacts.

Cheers
Lennart

aka tcastudios

[Lennart Wåhlin]

A typo of mine: I meant 1024×768 of coarse, as that is 4:3.

Cheers
Lennart

aka tcastudios

[Douglas Kerr]

Very interested in this technique I’ve seen a few places.

I didn’t think of using C4D to emulate before hand, why have you gone that route out of interest? Would have thought it’s quicker to place the objects and mark where they are positioned and then use visuals software like Modul8 or VDMX to map screens for each surface you want to project onto.

let me know how you get on.

[Nathan Byrne]

My goal is to give the illusion of parts of a stationary object are moving (i.e. a building facade). This would require creating 3D elements and shadows.

BTW … I working on tests as we speak and I’m still pulling my hair out.

If I put in the exact camera (projector) specs, in this case, as Lennart says a focal length of 14.75 and a aperture of 22.5,I’m still too far away from the object. Even disregarding the correct focal length and putting in a number that works 2 dimensionally (i.e. a focal length of 70mm), the three triangles don’t join correctly in the middle. When the projector (camera) is 68 inches away from the wall, the real life tetra pretty much takes up the whole screen. I’m currently considering my projector zoom maybe interfering, so I’m checking that now.

I keep reading of people using Cinema 4D to map out big theater productions, I wonder what there workflow is?

[Nathan Byrne]

Just as an update. I’ve been trying the fix the perspective problem, by getting the three sides of the pyramid to join up. I went back to Lennart’s DOF calculations and used modul8 to to resize, reposition etc. The result was a bust, it’s perspective is still not correct.

My theory is that the the C4D camera projects symmetrically (i.e. the same height, north and south of the camera’s center), while the real projector only projects north. The projector is designed to sit on a desk and project so the bottom of the projected image is a couple of inches above the height of the desk.

This difference in lens throw rotation would certainly alter the prospective of the objects in the scene. Is there a way to adjust the throw rotation and dimensions of a camera?