[yt-dev] camera rotation problem

[Geoffrey So]

In my email that's exactly what I tried, getting rid of the rot_vector on
line 17

"I've modified Sam's script to image the entire box, because it's harder to
see the effect if we're looking at a sphere
http://paste.yt-project.org/show/2689/
This script will produce the strange rotation, if the rot_vector is taken
out on line 17, then the rotation about the camera up is recovered.  But
that's not what was done before by yt and not what I wanted."

and I get the video here:
curl -O http://lca.ucsd.edu/~gso/test_movies/no_rot_vector.mpg

the movie above is rotation centered at at the middle of the data, but
around the "up" axis of the camera, not the "z" axis of the data with a
constant azimuthal angle, which rotation USED to do, shown here:

curl -O http://lca.ucsd.edu/~gso/test_movies/Density.avi

From
G.S.


On Thu, Sep 13, 2012 at 12:40 PM, Sam Skillman <samskillman at gmail.com>wrote:

> Hi Geoffrey,
>
> Can you try setting steady_north=True, north_vector=[0,0,1], and not
> specify a rot_vector in the rotation call?
>
> Sam
>
> On Thu, Sep 13, 2012 at 12:51 PM, Geoffrey So <gsiisg at gmail.com> wrote:
>
>> Short version:
>>
>> The following movie shows what's possible with yt-dev ~2.1
>> The camera rotates about z axis of the data with a constant azimuthal
>> angle w.r.t the z of the data:
>> curl -O http://lca.ucsd.edu/~gso/test_movies/Density.avi
>>
>> The following movies shows what happens now if I have a rotation vector
>> or no rotation vector
>>
>> Weird camera rotation:
>> curl -O http://lca.ucsd.edu/~gso/test_movies/with_rot_vector.mpg
>> Camera rotates about the "up" axis of the camera:
>> curl -O http://lca.ucsd.edu/~gso/test_movies/no_rot_vector.mpg
>>
>> Long version:
>>
>> I brought this issue up a while back but got distracted before it was
>> resolved, and over past two days did more digging/testing.
>>
>> symptom:
>>
>> I cannot rotate the camera about the z axis of the data while keeping the
>> azimuthal angle constant anymore, where as I could do this before in I
>> believe yt-dev 2.1ish.
>>
>> What I tried/found:
>>
>> I thought I mailed the dev list but couldn't dig it out of the yt-dev
>> archive, so maybe I only complained in IRC before.  This thread is the
>> latter portion where Nathan and Sam were helping me with helpful
>> suggestions and what to try.
>>
>> http://lists.spacepope.org/htdig.cgi/yt-dev-spacepope.org/2012-August/002267.html
>> The example script Sam provided (by not specifying the north_vector) will
>> rotate the camera about the camera's z (up) axis, but not the data's z
>> axis, if looking at the image, what I am trying to do is have the camera
>> rotate around the disk about the axis normal to the disk's plane (assume
>> disk is in x-y plane).
>>
>> I tried playing with the north_vector, steady_north in the camera object,
>> and the rot_vector in cam.rotation, made sure the vectors are normalized.
>>
>> I found that if I specify the normal vector (usually designated "L" in
>> example scripts) as the x or -x axis, and the north vector as the z axis, I
>> can look at the data cube (in this case Enzo data), and watch it rotate
>> about the z axis, the behavior I expected.  However, if my L is tilted not
>> 90 degrees (non x or y axis), no matter what I specify as the north vector,
>> the rotation angle changes and the cube wobbles or precesses.
>>
>> I've modified Sam's script to image the entire box, because it's harder
>> to see the effect if we're looking at a sphere
>> http://paste.yt-project.org/show/2689/
>> This script will produce the strange rotation, if the rot_vector is taken
>> out on line 17, then the rotation about the camera up is recovered.  But
>> that's not what was done before and not what I wanted.
>>
>> I also wrote the script to reproduce the effect I wanted with the
>> rotation, but this is a lot more work than before.  I have to specify a new
>> L and a new up angle for the camera for every frame to get back the effect
>> I wanted.
>> http://paste.yt-project.org/show/2690/
>>
>> Hope this help track down the problem, cam.rotation is so much simpler to
>> use :-)
>>
>> From
>> G.S.
>>
>> _______________________________________________
>> yt-dev mailing list
>> yt-dev at lists.spacepope.org
>> http://lists.spacepope.org/listinfo.cgi/yt-dev-spacepope.org
>>
>>
>
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