"get_position" - Viewing Center

Molecule Tutorials - Herong's Tutorial Examples

∟"get_position" - Viewing Center

This section provides a tutorial on how to use the 'get_position' command to see the viewing center location in the model space in PyMol.

If you want to know the camera viewing center location in the model space, you can run the "get_position" command.

For example, the following PyMol session shows the viewing center is located at the center of the methane molecule by default:

PyMOL>delete all
PyMOL>load Carbon-Atom.sdf
PyMOL>h_add

PyMOL>get_position
 cmd.get_position: [   0.840,  -1.030,  -0.000]

PyMOL>get_extent id 1
 cmd.extent: min: [   0.840,  -1.030,   0.000]
 cmd.extent: max: [   0.840,  -1.030,   0.000]

But if the camera is moved, the viewing center is moved accordingly in the opposite direction:

PyMOL>move x, 0.2

PyMOL>get_position
 cmd.get_position: [   0.649,  -0.971,   0.010]

PyMOL>get_extent id 1
 cmd.extent: min: [   0.840,  -1.030,   0.000]
 cmd.extent: max: [   0.840,  -1.030,   0.000]

Of course, we can translate the entire molecule back to match the viewing center:

PyMOL>translate [-0.2, 0.0, 0.0]
PyMOL>get_position
 cmd.get_position: [   0.649,  -0.971,   0.010]
PyMOL>get_extent id 1
 cmd.extent: min: [   0.649,  -0.971,   0.010]
 cmd.extent: max: [   0.649,  -0.971,   0.010]