A small change to a molecular model can have consequences beyond the atom or residue you meant to touch. Often, the hard part is not making a change—it is being certain you selected the right thing, understanding its current properties, and knowing how to check the result. A simple sequence can make everyday modeling work more deliberate: select, inspect, measure, then use history when you need to retrace your steps.
1. Begin with the scope of your selection
In a molecular structure, “the thing I want to work on” could mean an atom, a residue, a molecule, or another node. Before inspecting or editing, make the selection step explicit. SAMSON supports selecting nodes through commands, editors, filters, or the Node Specification Language (NSL). The useful habit is to pause and ask: What exactly is selected, and is that the level of detail I intend to work with?
This question helps prevent a common source of confusion: acting on a broader or narrower part of the structure than intended. If the next task is to check one residue, for example, confirm that the selection corresponds to the object you want to inspect rather than assuming the visible highlight tells the whole story.
2. Inspect before you edit
Once you have selected the relevant nodes, use the Inspector to check their properties. Inspection gives you a chance to understand the current state before changing it. If a property needs adjustment, the same step helps you connect the intended edit to the selected nodes.
A useful pause here is to state the purpose of the change in plain language: what property are you checking, and what do you expect to learn or adjust? This does not replace careful review, but it can make it easier to notice when the selection and the task do not match.
3. Measure when geometry matters
Visual appearance alone may not answer a geometric question. When you need to check a distance, angle, or dihedral, use a measurement rather than relying only on how the structure looks on screen. SAMSON’s measuring workflow also supports saving measurement labels, which can help keep a geometric check available as part of your work.
Choose the measurement that matches the question you are asking. A distance, an angle, and a dihedral describe different geometric relationships; measuring the wrong one can produce a precise value that does not address the problem. If you are not checking geometry, you can leave this step aside and return to it when needed.
4. Treat history as part of the workflow
Exploration involves trying things. SAMSON’s history tools let you move backward and forward through document changes with undo and redo. Rather than treating these tools as an emergency measure, make them part of a careful trial-and-review routine: note the change you are testing, inspect the result, and use history to move through changes if the outcome is not what you intended.
This is especially useful when you are learning an unfamiliar workflow or comparing possible edits. It gives you a way to navigate document changes while you work, without having to assume that every experiment must be the final version.
A practical sequence to remember
- Select: identify the nodes relevant to the task.
- Inspect: check their properties before making an adjustment.
- Measure: use a distance, angle, or dihedral when geometry is the question.
- Review with history: move backward or forward through changes as needed.
You do not need to use every step for every task. For checking a property, selection and inspection may be enough. For a geometry check, selection and measurement may be the focus. The value is in choosing the steps that match the question, instead of making changes first and trying to work out what happened afterward.
For the detailed workflows and related topics, read the SAMSON guide to working with structures.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.