A small change to a molecular model can have a larger effect than expected—especially if the wrong atoms, residues, or molecules are selected. And when you are exploring a structure, it is easy to lose track of what changed along the way. A dependable workflow can help: select deliberately, inspect before editing, measure when geometry matters, and use history to move backward or forward through document changes.
This approach is useful whether you are making a planned adjustment or simply investigating a structure. It does not require you to master every tool first. Instead, it gives you a practical sequence for reducing avoidable mistakes.
1. Make selection your first check
Selection determines which nodes you are working with, so it is worth treating it as a scope check rather than a formality. Before inspecting or editing, ask: What exactly is selected? The intended target might be an atom, a residue, a molecule, or another node in the document.
SAMSON supports selecting nodes with commands, editors, filters, or the Node Specification Language (NSL). These are different ways to express what you want to work with. Whichever method you use, pause to confirm the resulting selection before moving on. If the selection is broader or narrower than intended, correct it first. That simple habit can prevent you from interpreting or changing the wrong part of a system.
If you are new to this workflow, begin with the Selecting guide.
2. Inspect before you adjust
Once the target is selected, inspect its properties before changing anything. The Inspector is where you can check and adjust node properties. Looking first helps you understand the current state and gives you a point of comparison if you later need to review what you changed.
A useful pause is to name your intention in plain language: What property am I checking? What do I expect to change? Which selected nodes should that change affect? If you cannot answer those questions, return to the selection and inspection steps rather than making a speculative edit.
For details on checking and adjusting properties, see Inspecting.
3. Use measurements to answer geometric questions
When your question is about geometry, a visual impression may not be enough. SAMSON measurements can be used to check distances, angles, and dihedrals, and measurement labels can be saved. Choose the measurement that matches the question: a distance for separation, an angle for a three-point relationship, or a dihedral for a four-point relationship.
Measurements are most useful when they are tied to a specific question. For example: Am I checking whether two parts are close to one another? Do I need to compare an angle or a torsion-like relationship? Decide what you need to know, make the relevant measurement, and keep the result if you will want to refer to it later. The Measuring guide covers these checks.
4. Treat history as part of the workflow
Undo and redo are not just emergency controls. They let you explore changes while retaining a way to move backward and forward through document history. If an edit does not have the result you expected, history gives you a route back through changes. If you are unsure whether to proceed, knowing that history is available can make careful trial and error less stressful.
Still, history works best alongside deliberate selection and inspection—not instead of them. Before changing a structure, know what is selected; after a change, check whether the result matches your intention. When you need a refresher, consult History: Undo and redo.
A short pre-edit checklist
- Target: Have I selected the intended nodes?
- Context: Have I checked their relevant properties?
- Question: Would a distance, angle, or dihedral measurement help?
- Recovery: Do I know how to use undo and redo if the result is not what I intended?
Following these steps turns structure work into a sequence of small, checkable decisions. You do not need to measure every geometry or inspect every property; focus on the checks that match the task. To explore the complete workflow and choose what to read next, see Work with structures.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.