Displaying the render outputs of three scenes side-by-side

Hello. I’m having a problem that I’d like to try to solve using only the compositor.

I have three scenes: “north” “east” “south”.

The “north” scene contains all the actual objects, and the “east” and “south” scenes contain linked copies of all the objects in the “north” scene, only with different cameras.

Each scene produces a 512x512 image.

I’d like to take the images produced by these three scenes, and display them side-by-side, resulting in a 1536x512 image.

Essentially, I have these images:

http://waste.io7m.com/2014/08/19/want/e.png
http://waste.io7m.com/2014/08/19/want/n.png
http://waste.io7m.com/2014/08/19/want/s.png

And want to produce this image:

http://waste.io7m.com/2014/08/19/want/stitched.png

Having searched a bit, it seems that the correct way to do this is to create another scene with the render output size set to 1536x512, and then use Translate nodes to position the render outputs of the input scenes to their correct places on the larger canvas.

The problem: When I attach the image output of a RenderLayers node from any scene to the compositor output, the scene is rendered as if the original scene was at 1536x512 (which effectively changes the aspect ratio and results in a different image):

http://waste.io7m.com/2014/08/19/want/n_bad.png

The blend file is here:

http://waste.io7m.com/2014/08/19/want/spires.blend

Any idea how I could do this correctly?

It isn’t perfect, but maybe this can help?
spires set up.blend (1.95 MB)

Hi. Thanks for the attempt, but that still has the same issue. The output looks like:

http://waste.io7m.com/2014/08/19/wrong.png

Note that it’s the result of taking the incorrect results and scaling them to 512x512, and then translating. The actual issue is that each image is rendered as 1536x512 in the first place (meaning the aspect ratio is incorrect and as a result, the floor is cropped out of the image).

Oops, I completely missed that. The only idea I’ve got then is to increase the height of the final image as well, maintaining the aspect ratio, and cropping all left-over bits out in post.
spires another try.blend (1.95 MB)

Does this do the trick?

Attachments

spires.blend (1.95 MB)