about the depth of NERF

[xubin1994]

Hello, I have a question about when use NGP to render depth. It seems that NERF uses the distance of the sampling point to render the depth. It uses the distance from (x, y, z) to the origin (0, 0, 0) instead of the depth of z. So is it correct to use NERF to render the depth to disp here? Is there a problem?

[wtyuan96]

The depth value is calculated by integration of t value, which is along the z axis.
Remember that the camera ray r(t)=o+td.