VRayStereoscopic

enabled – Turns the VRayStereoscopic helper on or off. 

eye distance – Specifies the eye distance for which the stereoscopic image will be rendered. This parameter is ignored if the current camera has a VRayStereoRig controller, which causes the position of the left and right cameras to be taken from the VRayStereoRig controller itself.

specify focus  – When enabled, defines the point of focus with the focus distance parameter.

focus method – Specifies one of the three following focus methods for the two views. This parameter is ignored if the current render camera has a VRayStereoRig controller.

None – Both cameras have their focus points directly in front of them. 
Rotation – The stereoscopic effect is achieved by rotating the left and right views so that their focus points coincide at the distance from the eyes where the lines of sight for each eye converge called fusion distance. 
Shear – The orientation of both views remains the same but each eye's view is sheared along z so that the two frustums converge at the fusion distance.

interocular method – Specifies how the two virtual cameras will be placed in relation to the real camera in the scene. This parameter is ignored if the current render camera has a VRayStereoRig controller.

Shift both – Both virtual cameras will be shifted in opposite directions at a distance equal to half of the eye distance. 
Shift left – The virtual cameras are shifted to the left so that the right camera takes the position of the original camera. The left camera is shifted to the left at a distance equal to the eye distance. 
Shift right – The virtual cameras are shifted to the right so that the left camera takes the position of the original camera. The right camera is shifted to the right at a distance equal to the eye distance. 

view – Specifies which of the stereoscopic views will be rendered. 

Both – Both views will be rendered side by side. 
Left – Only the left view will be rendered. 
Right – Only the right view will be rendered. 

adjust resolution – When enabled, this option will automatically adjust the resolution for the final image rendered. For example, if Both is selected for view and the specified image resolution for the render is 640x480, the resulting render will be a single image with a resolution of 1280x480 with both views side by side.

output layout – Specifies the format in which the Stereoscopic renders are output to the V-Ray frame buffer.

Side-by-Side – Arranges the cameras side by side. 
Top-Bottom – Arranges the cameras one on top of another.

show cones – Controls when to show the cones of the virtual cameras created by the stereo rig. Only the cones of cameras assigned to a viewport will be shown. 

Selected – The cones will be shown only when the stereo rig is selected. 
Always – The cones will always be shown. 
Never – The cones will always be hidden.

The options in this section are used when rendering a panoramic view with stereoscopy (for example a Spherical camera with FOV=360 degrees). These options allow us to avoid artifacts when looking upward and downward. This is achieved by gradually decreasing the eye distance and thus the stereoscopic effect. The eye distance value is kept the same until the viewing angle reaches the angles specified in the properties below after which the eye distance is gradually decreased until it reaches a value of 0 when looking directly downwards or upwards.

top/bottom merge angle – Specifies the viewing angle (0 degrees is the horizontal plane) at which the pole merging effect described above starts.