Hello!
For these two tests, there are no rays being cast—all we’re doing here is creating an intersection record which we’re arbitrarily saying exists at t=1. You could set t=2, but it would make no difference, because the normal calculation is independent of t. For these smooth triangles, the only parameters that matter are u and v (and, of course, the triangle itself).
Does that make sense? Is there something I could be describing better?
Thanks!
Jamis