Mistake in Your Molecular Model? Here’s How to Safely Undo It in SAMSON

Whether you’re tweaking geometries, testing force field parameters, or building complex biomolecular assemblies, making changes efficiently and confidently is key. But with complexity comes a familiar concern among molecular modelers: what if you make a mistake and can’t go back?

When working on a molecular model, the ability to undo and redo your changes isn’t just a convenience—it can be a decisive factor between smooth exploration and frustrating do-overs. That’s where SAMSON’s History system steps in.

Document histories: working in parallel without the fear of loss

In SAMSON, each document you work on has its own independent action history. This is especially useful if you’re juggling multiple projects or comparing structural hypotheses side by side. You can undo or redo actions in one document while another remains untouched. This means less risk and more confidence with every edit.

Accessing the History View

You can open the History View in SAMSON by navigating to Interface > History or using the shortcut:

• Ctrl + 3 on Windows and Linux
• Cmd + 3 on macOS

This opens a visual timeline of your actions so you can easily click backward or forward through states. Each modification you make—adding an atom, editing geometry, changing settings—is written as a step in the list. Clicking any step lets you instantly revert to that snapshot of your project.

Keyboard shortcuts for undo and redo

For quick changes, SAMSON supports common keyboard shortcuts:

• Undo: Ctrl + Z (Windows/Linux) or Cmd + Z (macOS)
• Redo: Ctrl + Y (Windows/Linux) or Cmd + Y (macOS)

These work in the background to let you toggle recent actions without needing to switch views—great when you’re focused on testing a new hypothesis and want to iterate fast.

What can you undo—and what you can’t

While SAMSON allows you to undo or redo most actions, there are some cases where actions aren’t reversible. This typically involves operations that significantly change the structure or involve external data (like downloads). Importantly, if a non-undoable action occurs after some undoable ones, you might not be able to step back past that point.

Visualizing your workflow evolution

One of the often-overlooked benefits of the History View is that it gives you a visual map of your modeling session. This is helpful not only for undoing but also for reflecting on how your molecular model has evolved. Think of it as a mini version-control system built into your modeling platform.

The ability to revert confidently lets you experiment more freely—trying that unusual parameter, mutating the structure one more time, or exploring what happens when you apply a different simulation scheme—all without needing to save a dozen backup files.

To learn more, visit the original documentation here: https://documentation.samson-connect.net/users/latest/history/

SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON from https://www.samson-connect.net.