Hendrik Proosa wrote:Chad Capeland wrote:Expected. There's no "correct" way to render stereoscopic spherical projections.
Yes there is. Pixel-wide slicing with stereo rig rotating on the point between the cameras. This gives the best possible solution for 360 panoramic stereo with minimal artifacts. There are technicalities involved, but overall it is the correct way compared to other ways (cubic renders stitched, wide slices or whatnot).
Hi Hendrik.
Pixel wide slicing is what a raytraced omni-directional stereo lens shader does but with extra refinements added on top vs doing a brute force approach of rendering 3840 vertical strips as 3840 separate video frames and then merging them together manually for each sequence of a video for the left and right eyes...
Chad has used Domemaster3D and other lens shaders on commercial projects so he knows how to do panoramic stereo rendering.
I have programmed 360/VR stereo lens shaders in the past for fulldome and LatLong stereo imagery that work in mental ray, V-Ray, and Arnold so I have also done that task as a developer.
The original poster was asking for a 100% consistent pixel accurate alignment between a V-Ray for Maya, and Fusion 360/VR Stereo rendering. He even did frame differencing comparisons. That is very thorough in what he wants to see as the end output matching quality.
If you don't have both packages using the same exact stereo rendering approaches internally you won't get the same results. The formulas that are used for 2D mono LatLong output will be able to give you a pixel accurate alignment.
For 360/VR LatLong stereo output it is completely arbitrary how each renderer's built-in omni-directional stereo lens shader computes the stereo offsets and math between the left and right eye views when you want to layer on extra levels of complexity like zero parallax adjustments, and pole fading.
IMHO pixel-wide slicing by itself without stereo fadeout pole corrections applied from an
actual compiled lens shader won't give you a 100% satisfactory result in the zenith and nadir regions as you will get a swirl like artifact that shows up on textured surfaces like a carpet in an interior scene.