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Edit
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Selection
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- `Click` an atom to select it. Click again to deselect.
- `Shift + drag` to box-select multiple atoms (selection accumulates).
- `Shift + Alt + drag` to lasso-select multiple atoms (selection accumulates).

Advanced Selection
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Draw a mesh primitive and select atoms inside it.

Group-based Selection
----------------------
Tag atoms into named groups and select them later by group name. Each atom can
belong to multiple groups.

Example (JS):

.. code-block:: javascript

   // add selected atoms to a group
   editor.ops.atoms.AddAtomsToGroupOperation({ group: "molecule" });
   // remove selected atoms from a group
   editor.ops.atoms.RemoveAtomsFromGroupOperation({ group: "molecule" });
   // clear a group from all atoms
   editor.ops.atoms.ClearGroupOperation({ group: "molecule" });
   // select atoms by group
   editor.ops.selection.SelectByGroup({ group: "molecule" });

You can also manage groups directly on the Atoms object:

.. code-block:: javascript

   atoms.addAtomsToGroup([0, 1, 2], "surface");
   const indices = atoms.getGroupIndices("surface");

Move, Rotate, Scale
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Select atoms and use keyboard shortcuts to transform them, then move the mouse
to apply the transform and click to confirm.

- ``g`` translate
- ``r`` rotate
- ``s`` scale

Rotation defaults to the camera axis through the selection center.
To rotate around a custom axis, press ``r`` to enter rotate mode, then press ``a`` and click one or two atoms, then press ``a`` again to exit axis picking.
One atom sets the rotation center (camera axis), two atoms define the bond axis.
The axis is shown with orange crosses and a long orange line (for two atoms), and stays active until you redefine it.
Press ``a`` again to exit axis picking and rotate; click an axis atom again to deselect it.
Press ``r`` then ``x``, ``y``, or ``z`` to lock rotation to a world axis (press the same key again to unlock).

Translate Axis Lock
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Press ``g`` to translate, then press ``x``, ``y``, or ``z`` to lock movement to that axis.
To translate along an atom-defined axis, press ``g`` then ``a`` and click two atoms, then press ``a`` again to exit axis picking.
To translate in an atom-defined plane, press ``g`` then ``a`` and click three atoms, press ``a`` again to exit axis picking, then press ``p`` for plane or ``n`` for normal.

- ``g``, move
- ``r``, rotate
- ``d``, copy and move
- ``Delete`` or ``x``, delete the selected atoms