Re: The peak of the sine . . .
Hi, Nathan.
Yes, it does look like a shadow -- but it's not.
Where the curve becomes perpendicular to the line of vision is abrupt. This is a very small portion of the overall curve, and it will be constant from one end of a cylinder to the other, or slightly spreading in a cone shape (depending upon the cone’s profile). A Sphere would be a small disk of apparent emptiness. The shape of the shadowed, or vacant, region would follow the same pattern as would reflected.
The spread shown is consistent with the expected cone effect,
Dan