povray wrote:
> You've run into a pitfall with look_at.  Pointing the
> camera directly up or down that way gets it confused.

POV-Ray does not get confused at all!  The proper use of look_at is clearly 
outlined in the documentation.  there are no workaround necessary, just 
reading the documentation is sufficient :-)

In order to use look_at to determine the orientation of the camera, POV-Ray 
needs to compute cross product with the "sky" vector.  The default direction 
of the "sky" vector is the y-axis.  Consequently, if look_at - location 
yields a direction vectors also on the y-axis, there is no valid cross 
product and thus look_at will not work as expected.

As said, this is all in much more detail explained in the documentation. 
Thus, for the proper use of the "sky" vector, please consult the POV-Ray 
user reference, online for example at "2.3.1.1.2 The Sky Vector" 
<http://www.povray.org/documentation/view/3.6.1/246/>.

	Thorsten

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