A small modeling mistake can start with something deceptively simple: the wrong atoms are selected, a property is changed before it has been checked, or a measurement is made between unintended points. When you are working with a complex structure, it helps to treat selection, inspection, measurement, and history as one connected safety routine—not as separate features to remember only when something goes wrong.
The idea is straightforward: confirm what you are working on, understand its current state, check relevant geometry, and know how to retrace a change. This approach is useful whether you are exploring a structure for the first time or preparing to edit it.
1. Make selection a deliberate first step
Selection determines which nodes later actions will concern. Before inspecting or changing anything, pause to establish what you intend to work with: an atom, residue, molecule, or another node. SAMSON supports selecting nodes with commands, editors, filters, or the Node Specification Language (NSL), so you can choose an approach suited to the task.
A useful habit is to state the target in plain language before selecting it: for example, “the residue I want to inspect” or “the nodes I need for this geometry check.” Then verify that the selection matches that intention before moving on. This simple checkpoint can prevent a mismatch between what you meant to act on and what is actually selected.
If you need a refresher on selection methods, start with Selecting.
2. Inspect before editing
Once the intended nodes are selected, check their properties in the Inspector. Inspection gives you a chance to understand the current state before deciding whether a change is needed. That distinction matters: a value that looks unexpected may be correct for the particular node or context, while an assumed value may be wrong.
Make the question specific. Are you checking a property, or do you intend to adjust it? If you are only trying to understand the structure, inspection may be all you need. If you do make an edit, keep track of what you changed so that you can assess the result afterward. For the relevant workflow, see Inspecting.
3. Measure when geometry is the question
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. Measurements can also be saved as labels, which is useful when you want to keep a geometric check visible in the document.
Before measuring, return to the selection question: are the nodes involved in the measurement the ones you intended? A clear selection and a clearly stated question—such as “What is this distance?”—make it easier to interpret the result. See Measuring for the measurement workflow.
4. Treat history as part of the workflow
Undo and redo are not just emergency buttons. They let you move backward and forward through document changes while you work, making it easier to explore an edit and review its effect. If a result is not what you expected, use history to recover rather than trying to repair the document by guesswork.
It is still worth pausing before an action: understand what is selected, know what you are changing, and check the result afterward. History is a way to navigate changes, not a substitute for checking them. Learn more in History: Undo and redo.
A compact routine to keep nearby
- Select: Identify the nodes relevant to the task and verify the selection.
- Inspect: Check the properties before deciding whether to edit.
- Measure: Use a distance, angle, or dihedral measurement when geometry is the question.
- Review: Check the outcome and use undo or redo if you need to move through changes.
This sequence is useful because each step answers a different question: What am I working on? What is its current state? What does its geometry tell me? How can I recover if the result is not right? You do not need every step for every task. For example, a quick property check may not require a measurement, while a geometry check may not involve editing at all. Choose the steps that fit the work, but keep selection verification at the beginning.
For the complete overview and suggested paths into these workflows, visit Work with structures.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.