Re: Problem with FindNormalFast at a TGeoScaledShape

Hi Corey,
I am looking into it and will let you know, Regards,
Andrei

Corey Reed wrote:
> Hi,
>
> I believe FindNormalFast is not giving the correct normal at the surface
> of my TGeoScaledShape.
>
> I'm stepping through my geometry (half a sphere plus an ellipsoid plus a
> cone segment, all shells) with FindNextBoundaryAndStep and then asking
> for the normal from FindNormalFast.
>
> Here is an example of a situation where there seems to be a problem:
>
> http://www.nikhef.nl/~cjreed/pmtReflectExample.png
>
> The track is the red line. The normal is shown by the blue line, and
> does not seem to actually be normal to the surface.
>
> The result is that the "reflection" winds up sending the photon out of
> the volume!
>
> The macro to reproduce this situation can be found at:
>
> http://www.nikhef.nl/~cjreed/testGeoTracker.C
>
> I have tried both Root v5.24.00 and v5.26.00b on Linux-x86_64 and gotten
> the same results.
>
> Thanks for your help!
>
> - Corey
>
>
> PS - FindNextBoundaryAndStep seems to be going to the outer edge of the
> shell rather than the inner. Should I have expected this? Why don't I
> get two boundary points, one at the inner surface of the shell and one
> at the outer surface?
>
Received on Tue Mar 23 2010 - 08:28:51 CET