Recording and playing camera paths
Gaia Sky offers the possibility to record camera paths out of the
box and later play them. These camera paths are saved in a .gsc
(for Gaia Sky Camera) file in $HOME/.gaiasky/camera
.
Camera path file format
The format of the file is pretty straightforward. It consists of a
.gsc
file with white spaces as delimiters, each row containing the
state of the camera and the time for a given frame. The state of the camera
consists of 9 double-precision floating point numbers, 3 for the
position and 3 for the direction vector and 3 for the up
vector.
The reference system used is explained in the Internal reference system section. The units are .
The format of each row is as follows:
long
- Time as defined by thegetTime()
function ofjava.util.Date
(here).double x3
- Position of the camera.double x3
- Direction vector of the camera.double x3
- Up vector of the camera.
Recording camera paths
Gaia Sky offers two possibilities as to how to record a camera path: real time recording and keyframes.
Real time recording
In order to start recording the camera path, click on the
REC
button next to the Camera section title in the GUI Controls window. The
REC
button will turn red , which indicates the camera is being
recorded.
In order to stop the recording and write the file, click again on
the red REC
button. The button will turn grey and a notification
will pop up indicating the location of the camera file. Camera files are
by default saved in the $HOME/.gaiasky/camera
directory.
Keyframe system
The keyframe system offers the possibility to create keyframes at specific positions
from which the camera file will be generated. In order start creating a keyframed
camera path, click on the |rec-key-icon-tray| REC
button. A new window will pop up
from which you’ll be able to create and manage the keyframes.
Keyframes can be saved and loaded to and from .gkf
files. These files only contain
the information on the keyframes themselves. Once the keyframes have been created, they can
be exported to a
.gsc
camera path file.
A graphical representation of keyframes is displayed in the 3D world. Keyframes can be selected and dragged with the right mouse button.
In order to generate the camera file, two types of interpolation are available: Catmull-Rom splines and linear
interpolation. Catmull-Rom splines produce smoothed paths which hit every keyframe. In this mode,
keyframes can be seams , meaning that the path is broken at that point.
Playing camera paths
In order to play a camera file, click on the
PLAY
icon next to the
REC
icon. This will prompt a list of available camera files in the
$HOME/.gaiasky/camera
folder.
You can also combine the camera file playback with the frame output system to
save each frame to a JPEG
image during playback. To do so, enable the Activate frame output automatically
checkbox in the preferences dialog as described in the Camera recording section.