what is dt mean in the coed

[neilgogogo]

In the code, I saw many dt in the code, I read the code but I have no idea what is dt correspond? It seems that dt and pos could determine the mip.

Many thanks

instant-ngp/src/testbed_nerf.cu

Line 628 in 7b37eee

dt = calc_dt(t, cone_angle);

[Tom94]

It's the step size for ray marching.

[JoanCharmant]

It's dt as in "derivative of t", t being the typical variable name used for the distance along a ray. position = origin + (t * direction). So dt is the displacement per step.