Precise control over molecular positions is essential for molecular modellers, especially when fine-tuning alignments, rotations, or constructing complex molecular arrangements. Fortunately, SAMSON offers a suite of tools called move editors to make this process intuitive, efficient, and highly adaptable. In this blog post, we’ll explore how move editors work and how to harness their power for your molecular modeling tasks.
Why Move Editors Matter for Molecular Modelers
Repositioning atoms, molecules, or even entire meshes when using molecular design platforms can be a tedious and error-prone task. Misalignments during such operations may lead to inaccurate results or hinder further steps like pattern creation or alignment to reference frames. SAMSON’s move editors provide precise and user-friendly solutions to eliminate guesswork when transforming or aligning objects in the viewport.
An Overview of Move Editors in SAMSON
The move editors in SAMSON allow you to translate, rotate, and align molecular structures via intuitive controllers. You can find these editors in the left-side menu of SAMSON’s viewport. The three main types available are:
- Displacer Editor – Ideal for quick displacements of objects in the camera plane.
- Local Move Editor – Translates and rotates objects along their principal axes, perfect for object-centric transformations.
- Global Move Editor – Enables translation or rotation along the global X, Y, and Z axes, suitable for aligning objects to the global reference frame.
Using the Local Move Editor: A Deep Dive
Let’s explore one of the most versatile tools, the Local Move Editor, in more detail.
The local move editor is activated using the shortcut M. Once selected, the editor displays an intuitive set of widgets for both translation and rotation:
- Central translation widget: Use this widget to translate objects in the camera plane.
- Axis translation widgets: Move objects along the principal axes of the selected objects.
- Plane widgets: Move objects constrained to a plane.
- Rotation widgets: Rotate objects along the principal axes or freely using the trackball widget.
You can modify movements with or without snapping. Adjust snapping preferences directly via the viewport or in the application preferences (under Interface > Preferences > Editors > Snapping).
Example: Translating in the Camera Plane
To translate a selected object in the camera plane:
- Select your object (e.g., an atom or molecule) using the rectangle selection editor.
- Press and drag the central translation widget to move the object in the desired direction. The editor will automatically display live positional shifts.
- If you need to cancel mid-translation, press Esc to restore the previous position. Otherwise, release the mouse button to finalize.
Example: Rotating Using the Trackball
To incorporate freeform angular adjustments:
- Select the trackball widget and hold the left mouse button.
- Rotate your mouse in the desired direction for real-time angular adjustments. If you want to cancel, simply press Esc.
- Release the mouse to apply the rotation.
Snapping: Adding Precision to Your Moves
For even greater precision, SAMSON offers a snapping functionality to lock movements or rotations at predefined intervals. For instance, setting translational snapping to 0.5Å or rotational snapping to 10° can help maintain uniformity. This is especially useful for placing symmetrical structures or building molecular patterns with specific constraints.
Undo and Alignment Options
What if you made a move you regret? Don’t worry, every adjustment you make with SAMSON’s move editors is fully undoable. Simply navigate to Edit > Undo to revert your last action, ensuring a stress-free editing experience.
Additionally, the local move editor offers alignment options through its widgets; right-clicking on a widget opens a context menu for quick alignment adjustments along global axes.
Conclusion
Mastering SAMSON move editors can greatly enhance your molecular design workflows, making it easier to precisely control how objects align, rotate, and transform. Whether you’re aligning structures to simulate a new conformation or placing atoms for a novel molecular structure, these tools are designed to save time and allow clever adjustments with minimal effort.
To dive deeper into the world of move editors and other tools in SAMSON, you can explore the full documentation at this link.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at www.samson-connect.net.