From the release notes ..."For sphere geometries the intersection filter gets now invoked for front and back hit."
This is slightly annoying as now I get two calls to the intersectFilter for each sphere. I would like to "ignore" the second hit ( I just care that the ray hit the sphere). I process each hit as it happens, so I have no record of the previous hit. Any suggestions on how to ignore the back hit? Although the change did not break my algorithm, it doubles the hit-processing time.
I found a simple solution. In the intersection routine find the "t" where the ray is closest to the center of the sphere. Compare this to the "tFar" of the ray in the the intersection filter. if tFar>t then it is the "back" intersection.