Cineversity

Hi:

I’m trying to figure out the best way to compose and render 3D cube walls so they look like they’re extruding into a large volume for a stage presentation.

I’ve attached a mockup which shows what it could look like from the perspective of an audience member.

The stage setup will have four walls with a projector sending an image to each wall.  Left, back, right and top.  The back wall will be taken up by Powerpoint-type stuff, but they want these abstract cubes on the side and top walls, rendered in such a way so that from the audience perspective you see the extrusion of the cubes.  If I put the camera in the middle of that virtual space the cubes would be rendered and projected head on, so from the audience perspective you’d just see squares.  I’m trying to figure out how to best force the perspective to get that apparent depth coming into the stage volume.

My first rough approach was to just render it in perspective then crop and corner pin a side into a 1080x1080 square (the pixel dimensions of the side panels) in After Effects.  It looks like that could work, but it seems like there could be a more streamlined approach you could do in C4D to avoid having to stretch and pin it, resulting in a loss of quality.  These wall elements will animate, like the cubes would extrude out of the “flat” walls in some way.  I don’t know if some sort of camera mapping in C4D would be a more efficient approach.  It seems like you’d have to do it in two passes, one to render the walls in perspective and another to camera map them to a square shape.  There probably isn’t any way to feed the view from a “live” camera to a texture and shoot that with a second camera for rendering, all in one pass.

I realize that the perspectives won’t line up properly for everyone in the audience, but I think they’d prefer this effect to simply rendering the cubes head on for each side, losing that depth.

Any thoughts or suggestions?

Thanks.

Shawn Marshall
Marshall Arts Motion Graphics

Hi Shawn,

The best way to get there is to set up several cameras as normal and extreme audience positions. To get the best outcome, but it will always be a problem…

I have done those projections in the early ‘80s for a stage production (with slides, etc!). From that experience and from the long time I work with camera projection, I would say that the side walls will not work for a certain amount of the audience. If these walls could be more turned to the audience the effect will be better. (If you follow the link below, I have recorded all essential knowledge for camera projection and its limitations!). However the further away the audience is, the less problematic it is.

The position for the projectors might be not as flexible as the best practice would suggest it. The left wall will have the best results when shown from the right half of the audience center point. Vice-Versa for the right. The ceiling from the middle of the audience. Not knowing if the audience sits in a square like room or in a long rectangle, makes it harder to tell.

If my assumptions are close, considering not knowing the space, the best or optimal viewing position would be determine for each wall where the C4D camera should be.

Each camera renders then a larger format than the projector can handle, which shouldn’t be a big problem.

These cameras will then be used for the Projection - but without the cubes, in the box like stage.

This projection can then be rendered with cameras that are exactly where the real projectors are in the theater. Which shouldn’t be to far off the middle point of the projection. Light falls off [inverse square] and with a projection more towards the audience , the image might not be able to be corrected by the projectors, and so the image is in the back larger, and even more darker.

If that needs to be done in one step per camera is perhaps up to you. I would do it in two steps, to have more control. To do it in one step [per camera/projection means that you have to use the MoGraph Camera Shader and adjust it very precisely with UV coordinates. My suggestion, do the two step. Not worth it other wise.

So - to summarize, in short, you need the projector data, at least the max resolution, and with the aid of C4D you can see where to place them, if that is not a given for various reason. (Best practice would be to know how much light you have if projected off axis for the left/right side of a single projection, to compensate for that.
People on the left will have zero 3D experience from the left wall and it gets better to the right sided audience for the left wall, then after a point it will get worse for the most right sided one. Again, vice versa.

All of that can be evaluated in C4D, as long as you know the final constellations..

My best wishes

P.S.: I couldn’t resist to capture this little one minute clip. You can download it.

https://www.amazon.com/clouddrive/share/t3erxmhq4PGdWUvayxd2ppW5xHHWVf5X9IO6p3FNLJs?ref_=cd_ph_share_link_copy

The scene file is attached as well. I have used here non parallel walls as I think that these allow for the best result.
All cubes from the walls should be invisible when you record the ceiling, and all cubes from the ceiling while recording the walls.

ENJOY.

File is here:
https://www.amazon.com/clouddrive/share/Q1lb20qys0GxUokLqDTmI3Nbt2hVNWDPE5Oqe2FFpdM?ref_=cd_ph_share_link_copy

Hi:

I usually get an email when I get replies to my posts, but not this time, so I would have responded sooner.  Thanks for taking the time to lay out your approach. 

I haven’t concerned myself with the positions of the projectors in this scenario.  The AV guys have told us they can keystone their projectors to fit the screens.

It looks like, though, you’d still have to go through C4D twice to generate the “flat” images for projection, once for the perspective render and once to make the camera-mapped image square.

What I ended up doing is placing the camera where an audience member sitting in the middle might be and rendering that out that view of the three surfaces.  I then took that image into After Effects and did some cropping and corner pin unstretching to distort those perspective views into flat, square images corresponding to the projected dimensions.  A mockup of the result can be seen here.

http://marshall-arts.net/Cineversity-Demos/CubeWallsmockupDemo.mp4

Our agency client has seen this and loves it.  It’s not perfect, but it works.  They’ve sent it along to the ultimate client.

Best.

Shawn

Hi Shawn,

You’re welcome. Thanks for the clip.

When I use my own projector, I can put it to an trapezoid projection as well, but mine has no option to compensate for the falloff in intensity. I’m certain the once used for the project will.

To go from the middle for all simplifies the first iteration.

My idea is, that the left audience will have no fun with the left wall anyway, so to move that projector to the right was the option to gain more for the people who can. On the end it is the fixed projection that has to convince.

I’m not certain if you noticed that I have turned the walls toward the audience a little bit, which increases the quality and the amount of people who get a decent effect. Perhaps a small difference, but I would play with it, as you mentioned that the back-wal has a power-point like presentation, which should be seen from anyone at any position, which might be not possible with an parallel wall approach. Perhaps it is not supposed to fill the back-wall. (I used here (back) cubes as well, but I know, they are not used here.)

=======

One Step Render

In the attached example, I have provided a one step per projector method. You need only to render out “Camera2.[0-3]” to get the walls. Adjust the position accordingly to your needs.

In short, the stage is captured with “Camera.0”, and with all cubes, perhaps in motion. As mentioned above, I would have only the cubes in the scene needed for the wall or ceiling, so the wall cubes do not show up in the ceiling or neighbor wall.

This goes then to a MoGraph Camera Shader which is projected in the same way (Pos/Rot) as the “Camera.0”, but now used as projection “Camera.CP”. Which gives an option to “capture the four flat parts, or distorted as needed.

“Camera.2 [0-3]” will then render what is needed. No step between needed. I would oversample (supersample) and scale down for better quality. (Just a thought).

I hope you enjoy this little one minute clip, which illustrates the flow and set-up.
https://www.amazon.com/clouddrive/share/M6PxNh9uXHWjNcZTyBygCnY8oWaE7kR0f3tf1oFLz5g?ref_=cd_ph_share_link_copy
You can download the clip, and the C4D file is here:
https://www.amazon.com/clouddrive/share/CvKAWqhNtOO3DfVcZ3jBuUdz3wLYXnAjRpqsvFMq7BQ?ref_=cd_ph_share_link_copy

My best wishes for the project

Neat, thanks.  I’ll play around with this one-step workflow.

I think the AV guys plan to angle out the side walls a little bit, like 5° each.  Other parts of the presentation will involve flying into a 3D model of a piece of consumer hardware, so I’ve had to work up a camera rig to shoot the back, left, right and top.  It’s basically just four cameras with 90° viewing angles rotated at right angles to each other.  The idea is you’re inside this piece of hardware.  The sort of problem I’m having is that the 4 views line up great if you’re standing in the middle of the cube, but from the audience perspective (outside of the cube) some of the angles will be kind of funky.  I haven’t been able to come up with a way to really compensate for that.

Cheers.

Shawn

You’re welcome, Shawn.

Inside of the cube is simple and if you stand in the center, that is how a six side projection for VR works. To get the audience involved, one has to capture it from an ideal position from audience POV. (… for each wall from my point of view, and turn the walls even more than 5º, but I repeat myself here).

As a side note: Beside Set design and stage design, I have worked back in the ‘90s on such concepts (VR) and if you like, here is an published article about.
https://plus.google.com/+DrSassiLA/posts/BQJU3pS2Bpe?pid=6203373218395580082&oid=110784099379805584044

Perhaps you might test an “old” theater effect. It is like a net, which is nearly invisible without light, but if projections or light hits it, with enough dark areas behind, it looks nearly opaque. If you get a good mix, just a view parts bright in an other wise dark image for this “net” will defining this “space” even more… Just a though. (All projectors must be then inside, and the net projector from the ceiling pointing to the floor, to not effect the other parts.

I had to googled the effect, since I lost all my “stage/light/cinematography” books back in Europe a while ago, based on water damage. This is a nice model explanation, not really what I meant but it gives the idea: https://www.youtube.com/watch?v=CTS8rs6zUT4

All the best

Hi:

Thanks for the input.  Unfortunately, I have no say in how this stuff will be projected.  That’s being handled by the agency and their AV guys in the U.K.

We did do a presentation for Intel 7-8 years ago in which elements were projected onto a transparent screen in front of the presenter.  They likened it to a hologram.

Shawn

My best wishes for this Project, Shawn.

Here’s the company that handled the presentation of these Intel animations back in the day:

http://musion.com

I was still using Lightwave back then.  I think it went over well, but the project was a nightmare of last-minute revisions.  I have a clear memory of working through the night until 8am or so to deliver the last few elements.  TNT, which is a cable channel here in the US, ran a Resident Evil movie marathon, which I had on for the whole night.

Shawn

Very nice, Shawn. This was certainly a lot of fun to have worked with them. Yes, the night shifts… Nice examples. I have to revisit this link later again. So many projects, nice!

Yes, I remember LW ;o) Thanks for sharing a little bit about your background. Always appreciated! :o)

Reminds me on a discotheque that I designed in the later ‘80s to finance another year at the University of the Arts in Berlin. “I was young and needed the money ;o)” I had the idea to project animations on the dance-floor from atop and in a little bit of smoke. I asked Sony to support me, and they came with a fridge sized projector, and three technicians. Was breathtaking to set that up. We had only spheres and cubes at that time as animation, but it worked out great. It was then published in a large German news paper.

Sorry about the tint of bragging, but I share this more based on my passion for all of this. Hence why I stick with my triangle of visual art: 3D, photography and movie-making.

My best wishes.