In computational molecular modeling, trial and error is often part of the discovery process. Whether you’re building a structural model, setting up a simulation, or analyzing a complex interaction, it’s common to make adjustments—some of which you’d rather undo. But what happens when you’ve made several changes, and you wish to revisit an earlier state? Does that mean you have to restart the building process from scratch?
Fortunately, SAMSON offers a built-in History system that helps you rewind—or fast forward—your molecular design timeline. This blog post explores how to use SAMSON’s History features to undo and redo actions efficiently, whether you’re building a protein-ligand complex or assembling a nanostructure.
Understanding the Per-Document History
Every document in SAMSON maintains its own list of undoable actions. This means your action history is always context-sensitive; changes made in one document won’t affect another. For molecular modelers working on multiple systems in parallel, this ensures a clean and safe workflow.
Accessing the History View
You can open the History View via the main menu by navigating to Interface > History, or simply use the keyboard shortcut Ctrl + 3 on Windows/Linux, or Cmd + 3 on macOS. This launches a panel displaying your sequence of actions in chronological order.
Going Back (Or Forward) in Time
In the History View, each operation appears as an entry in a list. Clicking an earlier action returns the document to the state it had after that operation was performed. It’s like flipping through a version-controlled timeline of your molecular project. If you move back and want to go forward again, simply jump to a more recent entry—assuming intervening non-undoable actions haven’t broken the chain (more on that below).
Alternatively, you can use traditional shortcuts:
- Undo: Ctrl + Z (Windows/Linux), or Cmd + Z (Mac)
- Redo: Ctrl + Y (Windows/Linux), or Cmd + Y (Mac)
Limitations and Best Practices
The system isn’t flawless—some operations aren’t undoable. These may interrupt the undo chain, meaning previous steps can’t always be reversed. For example, adding certain nodes or invoking external modules that bypass the standard history manager may not be tracked. When workflows involve alternating between modeling and simulation steps, it’s a good idea to save your document at key points, or better yet, use versioning and naming conventions to create checkpoints.
Why This Matters to Modelers
If you’ve ever spent hours building a biomolecular system, only to misplace a subunit or accidentally delete a chain, you know how frustrating it is to reconstruct everything from scratch. History navigation allows you to experiment confidently, knowing that any mistake—or even a series of them—can be rolled back with minimal disruption.
Undo and redo might sound like basic GUI functions, but in molecular design, where setups are nuanced and changes accumulate quickly, this simple feature can be a productivity lifesaver.
To learn more about history navigation in SAMSON, visit the full documentation at https://documentation.samson-connect.net/users/latest/history/.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at https://www.samson-connect.net.