Thank you so much for the rapid reply.
1. Sure. Even after the calibration, both eye fixations don't converge at the virtually infinite far object.
2. I knew the thread. Based on the geometry, the infinite far object is drawn at the same point in each display, right? Or the display of the vive is not alligned at the center?
3. I think this phenomenon is not Gaussian distribution...
4. Do you mean "convergence_distance_mm"? If so, yes it'll help me much. But it is not implemented yet, right?