I think the issue is that yt uses a left-handed coordinate system internally. This particular choice makes it so that if you create a volume rendering, off axis slice plot, or off axis projection it is oriented in the same way as a regular slice or projection. Of course if you don't like that convention you can always specify a north_vector.
If you want to transform to your sky coordinate frame you will need to come up with a more general transformation matrix rather than multiplying by x, y, and z scalars (i.e. a diagonal transformation matrix). Fortunately the orientation class already does the hard work for you, I think all you need to do is multiply the (x,y,z) vector by the orientation.unit_vectors matrix (maybe orientation.inv_matrix, sorry, this 3D geometry stuff always confuses me ;)
Hope that helps.
On 8/22/12 10:23 PM, John ZuHone wrote:
Hi all, and specifically to those of you with experience with the Orientation vectors...
Doing some testing, I set up an orienter like this:
orient = Orientation([0.0,0.0,1.0])
and the output of orient.unit_vectors is:
[array([ 0., -1., 0.]), array([ 1., 0., -0.]), array([ 0., 0., 1.])]
which I would have expected
[array([ 1., 0., 0.]), array([ 0., 1., 0.]), array([ 0., 0., 1.])]
although I know I could fix this by specifying a north_vector, why would the latter not be the default?
I'm asking because I was attempting to set up new coordinates like so:
orient = Orientation(L)
x_hat = orient.unit_vectors y_hat = orient.unit_vectors z_hat = orient.unit_vectors xsky = x*x_hat + y*x_hat + z*x_hat ysky = x*y_hat + y*y_hat + z*y_hat zsky = x*z_hat + y*z_hat + z*z_hat
but this will rotate the x,y plane by 90 degrees.
John _______________________________________________ yt-dev mailing list firstname.lastname@example.org http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org