Problem
I've been reconstructing point clouds from blender's Z-pass outputs; saving to .exr to capture the full detail. I've noticed that when I use the EEVEE engine flat surfaces are reconstructed flat - but using cycles the same captured Z pass includes radial distortion even when accounting for the camera intrinsics.
Linked Images
Cycles Z pass to point cloud Eevee Z pass to point cloud
At this point I'd be assuming that Eevee is taking Z distance from the camera, whereas Cycles is calculating the length of the path before intersection, but I can't find any confirmation of these different behaviours.