IRAY Camera - Stereo Lens Offset


1st time NVIDIA forum user and post. Please let me know if there is a better area for this inquiry. Thanks

I use Daz Studio 4.12 and use iRay when rendering. I have begun making 360 VR renders for viewing in my Oculus Quest. In Daz the camera object has a lens section that appears to only be used for IRay of which the ‘Spherical’ lens is used to make the equirectangular renders.

When making the stereo VR images I have done two methods and found they produce different results, but to my thinking they should be the same.

I’m hoping someone here on the forum can help explain the difference and maybe what could be done to rectify it.

Method 1 - 2 Cameras moved on the x-axis. The default distance measure in Daz is cm. For the left eye image I set the X-Translate param to -3.2. This is half the IDP of average 64mm between the eyes for most people. The right eye render uses a 2nd camera at +3.2.

Method 2 - 2 Cameras in x-axis center, set Stereo Lens Offset (mm). This parameter is in the Camera/Lens settings and I found the reference below in the IRAY Programmer’s Manual online:

Float32 mip_lens_stereo_offset = 0.0
Controls the distance between the center and the right camera position for stereo view.
Iray can render both the right and left stereo images in one pass. When the ICanvas
passed to the IRender_context::render() function has multiple layers iray will render
the right and left eye in one pass and store these in respectively the first and second layer
of the canvas (See “Rendering and canvases” (page 29)).

the setting shows mm so I set the left eye camera to -32 and right to 32. When I compare the output of both sets of renders I notice there is a distinct difference on the perspective on objects as they get closer to the camera.

When I put both renders together for viewing in Oculus Gallery I see the images produced from Method 2 with the stereo lens offset appear correct when viewing everywhere in 360. But the images with Method 1 distort not only worse on close objects, but perspective is also off especially in the area behind you.

Is there any information on the internal iray camera settings for Spherical renders and what specifically the Stereo Lens Offset is doing since it doesn’t appear to shift the camera ‘behind the scenes’ along the x-axis?