If you’re a molecular modeler or researcher, precise control over the positioning of molecular structures is an essential part of your workflow. Whether you’re setting up simulations, adjusting molecular orientations, or aligning structures for analysis, the ability to reposition objects with pinpoint accuracy can save you time and frustration. With SAMSON’s built-in move editors, you gain the power to translate and rotate objects intuitively and with great precision. Let’s explore how they can address this common modeling challenge.
What Are Move Editors?
Move editors provide tools for manipulating the positions and orientations of nodes in SAMSON. These nodes can include molecules, atoms, meshes, and other elements. Move editors enable you to make targeted translations and rotations along specific axes or within defined planes. SAMSON offers three primary move editors by default:
- Displacer: Move objects in the camera plane with ease. Shortcut: D.
- Local Move Editor: Translate and rotate structures along their principal axes with built-in rotation and translation widgets. Shortcut: M.
- Global Move Editor: Align objects using global reference frame axes (X, Y, Z) for consistent positioning. Shortcut: K.
How to Move Objects with Precision
To start, you’ll need to select the parts of the molecular structure you wish to move. In the SAMSON viewport, you can use the rectangle selection editor or refer to documented tips for selection.
Once selected, use any of the following tools for accurate translation and rotation:
Using the Displacer Editor
The displacer editor offers a straightforward way to move structures in the 2D plane of the camera. Simply click and drag the selection, watching it follow your pointer. For added precision, enable snapping to standard increments. This is particularly valuable for interactive simulations. 
Local Move Editor: In-Depth Control
The local move editor is ideal for more detailed operations, offering widgets for translations, rotations, and even trackball-type free rotations. For example:
- Drag translation widgets to move objects along principal axes or within the camera plane.
- Use rotation widgets for controlled angular adjustments around key axes.
- Enable snapping to enforce regular translation or rotational steps.
As an advanced feature, this editor allows dihedral angle adjustments. Simply click the bond and use the widget to modify the angle, as shown below:
Global Move Editor: Aligning with Confidence
When working with multiple structures, alignment relative to a global reference frame ensures consistency. The global move editor features similar widgets to its local counterpart but aligns movements along fixed X, Y, and Z axes. Want to rotate an entire set of objects around a defined pivot? Right-click on the desired widget, define the rotation center, and rotate with snapping set to your preferred resolution.
Using Snapping for Reproducibility
One of the most useful aspects of SAMSON’s movement tools is snapping. You can set translation snapping to values in angstroms (e.g., 0.5Å) or rotational snapping to degrees (e.g., 10°). The snapping options are accessible from the quick menu in the top-left corner of the viewport or from the preferences menu (Interface > Preferences > Editors > Snapping).
Here’s an example of snapping in action, where translations and rotations are performed with predefined steps:
From intuitive design tweaks to precise alignments and structured molecular assemblies, SAMSON’s move editors are tools you’ll wonder how you ever modeled without. Ready to dive deeper? Visit the official documentation page for Moving Objects in SAMSON.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at https://www.samson-connect.net.