Custom Pixel Aspect Ratio (After Effects CC 2014)

Question

Hi All,
How do you create a custom Pixel Aspect Ratio for After Effects CC 2014. I need a PAR of 3.3, as it would help me solve a technical problem i've been having with projection mapping.
I've tried editing the Interpretation Rules.txt file which was hidden within the Users\Appdata\Roaming\Adobe\After Effects\13.1 Folder. To remove the last # so i can at least see that I can set up a custom PAR.
But it doesn't appear in the drop down menu when creating a comp, or interpreting footage.
I've also made the same change to the Interpretation Rules.txt file in the Premiere PRO CC 2014\Plug-ins\en_US\ folder.
And I've restarted my PC after changes just incase Media Core wasn't updating itself properly.
I can see the Custom PAR as an export option out of Media Encoder. But thats not what i need. I need to be able to correct a render which had a PAR of 3.3 without losing pixel information, much like an Anamorphic workflow.
Anyway, Any help would be appreciated.
Thanks!
Evan

Answer 1

Hi Rick,
You're right, it's no known PAR... completely arbitrary and custom to this particular job. I'll run you through my process.
I have a projection surface (a basketball court) Which needs to have content designed onto it which is viewable from one perspective point (camera 1) in the stadium. The problem is that Camera 1's viewing angle to the court is quite shallow.
This is what Camera 1 sees:
I will be generating like this for the surface so that it looks like a deep 3d surface from "camera 1"
Now, the problem is that when I perspective correct the renders to fit what the projector will be projecting from straight down. There isn't enough pixel information for the height of the image. Meaning the pixels will smear.
This is the image that would be projected from a top mounted projector to achieve the 3d effect from the image above, you can see the loss of information in the the height pixels.
My solution for getting more information into the height is to render out of our 3d packages with a Pixel Aspect Ratio of 3.3. This was the sweet spot I found to get enough pixel information to match the pixel output of the projectors.
The resulting render looks like this (note, the angle of the camera hasn't changed)
As you can see, there is more height detail now, which will mean that that last row of pixels will be remain fairly sharp.
So, at this point, I can render from my 3d applications, and conform to the projector dimensions, with very little information loss in the height of the projected image, and without compromising my 3d persepctive.
I'm using the plugin "Camera Mapper" to project this render onto a plane which gets me the full frame of the projector at the right resolution, 4608 x 2304
The tricky part how to composite elements into the scene in an intuitive way.
If i want a horse to look like its jumping through the scene from "camera 1", like this:
Then in the that contains all the information, It will look like this:
Now that's all well and good, but it'll be harder to create realistic looking effects from this view, because they'll all need to be stretched.
I'd like to retain all the image information and just view the comp as though it's squished down.
I imagine this could be done easily by changing the comp settings to a PAR of 3.3.
That way, all the pixel information remains, but i can design in a realistically proportioned composition.
I hope that gets you up to speed on my issue, and my request for a solution.
So, in summary. I'll I'm really looking for is a way to customise the PAR options so that I have a custom available that I can apply to this, and only this scene.
Does this makes sense?
Cheers,
Evan