A misplaced move, an accidental edit, or a structure-building step that did not turn out as expected can interrupt molecular modeling. The first instinct is often to press Undo repeatedly—but if you are unsure how far back to go, repeated undoing can make it harder to find the state you wanted.
SAMSON provides a per-document History view that lets you inspect and move through document states. Instead of treating Undo as a blind rewind, use the history list to see the actions you can return to and choose a point that makes sense for your model.
Open the history for the document you are editing
Each SAMSON document has its own history of undoable actions. Open it from Interface > History, or use Ctrl+3 on Windows and Linux, or Cmd+3 on Mac. Keeping in mind that histories belong to individual documents can help when you have more than one document open: check that you are viewing the history for the document whose structure you intend to change.
Navigate to a useful state
In the History view, click an action to move through the document’s recorded states. This can be useful when you want to review the result of earlier work before deciding whether to continue from it. For example, after trying a sequence of structure edits or transformations, you can inspect earlier states and return to one before the changes you no longer want.
You can also use the commands in the Edit menu:
- Undo: Ctrl+Z on Windows and Linux; Cmd+Z on Mac.
- Redo: Ctrl+Y on Windows and Linux; Cmd+Y on Mac.
Undo and redo are convenient when you know the last action is the one to reverse or restore. When you are less certain, the History view gives you a way to move through the recorded states directly rather than relying only on repeated keyboard shortcuts.
Know the important limitation
History is not a guarantee that every operation can be reversed. Some operations are not undoable. The documentation also warns that when non-undoable operations occur between undoable ones, SAMSON may not be able to undo the later operations properly, and data loss may result.
That warning is especially relevant when you are experimenting with a model. If an operation seems important or difficult to reproduce, pause before relying on Undo as your only recovery plan. Use the History view to understand which recorded actions you are stepping through, and take care when moving back across a sequence that may include operations that cannot be undone.
A simple recovery routine
- Open the History view for the document you are working on.
- Find the action or state you want to return to, and click it to navigate through the history.
- Check the document before continuing with further edits.
- Use Redo if you want to move forward again through actions that can be restored.
This approach is useful during structure editing, building, and transformation experiments: it makes it easier to review your path and choose a previous state, while keeping the limits of undoability in mind.
For details, see the SAMSON History documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.