[yt-users] Volume rendering rotation

[Stella Offner]

Hi,

I am generating volume renderings using a direct_ray_cast call. If I set 
L = [na.sin(2*na.pi*frame/rotframes),na.cos(2*na.pi*frame/rotframes), 
0.0] (like Sam's python movie script) so that the consecutive images 
revolve, after 30 degrees of rotation the "up" vector of the output 
image suddenly rotates 90 degrees. The problem seems to be independent 
of the z coordinate of L. Is there something strange happening in the 
normalization of L within direct_ray_cast or am I missing something 
basic? I can rotate the png files back to the correct orientation before 
stringing them together but that is annoying.

Thanks,
Stella