Ceiling Warping help!

Warper & Mapping related questions

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Ceiling Warping help!

Postby neil » Mon Jun 23, 2014 4:29 pm

Hi everyone,

I have very recently started using the Coolux server and have been set a project that I am having trouble with and would really appreciate any advice that could help me solve the issues that I am coming up against.

For the event I have to project onto the ceiling of a ballroom the dimensions of which are roughly 30m long by 15m wide with semi circular ends to the ceiling to add another layer of complication the ceiling is a typical convex dome shape. The projectors (20k Christie roadsters) will be on a balcony roughly 4m from the ground floor and the same amount from the apex of the ceiling, they will be at apposing ends of the ballroom shooting down the length of the ballroom. The content to be shown on the ceiling will be a flag gently blowing in the 'wind'.

I have used other projection systems to deal with multiple projection blends on flat front and rear projection surfaces, but this cross projection warping onto a convex domed ceiling is really blowing my mind.

I have mocked the scenario in the office with two dektop projectors and listed below are the steps that I have taken, they definately are not correct I realise but as I mentioned this is new to me, I am hoping that it will be somethng simple that I have maybe not thought about and can easily fix?

I've got my coolux setup with a dual independant output I then open the warper software open a 5x5 FFD mesh and assign that to the sencond output then repeat that process for the first output. I then have turned the mesh on the first output on via the advanced menu by 90 degrees and then rotated the secondary output warp file by 270 degrees so that the two projections are on the same orientation, not sure if that is necessary but it seemed to make sense. I've then carried out all of the appropriate alterations to the to the FFD and mesh files untill they look correct. Then I export them as '.x' files after opening up my Manager software I drop the appropriate '.x' file to the correct output. For some reason the when I then place some content onto a layer the output bears no real resemblence to my altered '.x' warped files that I have just spent hours sorting out in the warper programme. On top of that the content is two seperate images not one continuous smooth flag, both starting in the centre of the projection.

I expect and hope that this is a relatively simple problem to over come, having watched some of the videos about coolux hopefully one of you legends will be able to point me in the right direction.

Much appreciarted
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Joined: Mon Jun 23, 2014 6:18 am

Re: Ceiling Warping help!

Postby claude.rivet » Wed Jul 02, 2014 7:53 pm

Here is the method I propose:

1- Do the maths and figure out your pixel space, at 15x30 two HD projectors will result in a 2160x1080 space with a blend of 1680 pixels. This is a huge blend, you could just overshoot one projector and be able to cover your ceiling completely, obviously the space and distance don't allow that and this is probably why you blend 2 projectors. My advice is that you blend for 256 pixels, or around that, giving a very smooth opacity curve. Obviously the content will be 2160x1080 BUT the pixel space will be 3584x1080, your image will be centered inside it.

2- Create a test pattern, one file, made using your event pixel space (3584x1080) and markers indicating where the content will start and end (a centered zone 2160 pixel wide), add a grid, an x from corner to corner and one circle in the middle and one in each corner of the content zone (2160x1080). Also place markers to indicate the blend (256 pixels centered)

3- Place the test pattern on a track and adjust the cameras position so that they blend for 256pixels (move camera1 to the left and camera2 to the right until the edge of the camera fit with the blend markers in your test pattern).

4- Start the projectors and orient your image via the projector, not Coolux, this is one less step and set of problems for you (ex: front ceiling, or front table...). So two facing projectors would have projector 1 as front table and projector 2 as front ceiling for example. Make sure the projector blend zone matches the camera blend zone (they WILL overshoot but you won't lose resolution).

5- Use dynamic warping, it will, by far, make the whole process much more friendly. Basically create an FFD (5x5 for example) and set the warper to advanced mode, in the last tab activate communication with pandora box and set the site and device of your first output, save the file as a .wrp file then export it as an index object (which gives you a .x). Change the site and device to your second output and save again as a .wrp. Place the index object in the mesh box of your output1 and output2 in PB and then in the aeon FX drag the warp effect in each of your output tracks (this will turn the output to black, it's temporary don't panic). Go back to the warper and open your output1.wrp file, manipulate any point in the FFD and the image will appear and you can manipulate it in real-time. Wysywyg mapping, pretty awesome, I highly recommend it. One little drawback: everytime you will close the client the next time you will open it the output will be black, just open the warper and from there open output1.wrp, select a point and move it back and forth one value, do the same with output2.wrp and there you go, the image is there all warped and everything. Once you are satisfied re-save the .wrp file so that all changes you made are kept for the next time you open it. For all this process I recommend using the test pattern you created in step 1. Or just plain use the flag but doing so may prevent you from seeing small distortion and linearity issues but it will work for the most part.

6- Once you are satisfied with your dynamic warp you can export the resulting FFD as a regular .x file (not an index object) and replace the index object in the output track with the regular .x file. Delete the warp FX from the track (you will find it in the track tree, not in the device pane). OR keep it in dynamic form, but keep in mind everytime you close and re-open the client you need to re-open the warper and wiggle a point for each output, this is how I personally do it and it sped up warping quite significantly.

All of this process will make sure the blend for you projector equals the overlap in your picture and minimize aftefacts and maximize resolution, it will also eliminate the guesswork. It will make warping far easier once you did it and figured out how it works.

Hope this helps!
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Joined: Tue Aug 07, 2012 5:40 pm

Re: Ceiling Warping help!

Postby Patrick Verhey » Fri Jul 11, 2014 9:40 am

Hi Claude,

thanks for the perfect workflow. There is nothing to add from our side :-)

best regards

Patrick Verhey
Patrick Verhey
Posts: 366
Joined: Fri Jul 11, 2008 11:49 am
Location: Cologne, Germany

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