Measuring distances, angles, and torsions between atoms is a common task in molecular modeling. It helps you validate structures, prepare simulations, and analyze chemical interactions. But if you’ve ever had to re-do the same measurement just because it disappeared when you clicked something else, you’re not alone.
Thankfully, SAMSON offers a simple yet powerful way to manage and preserve measurements—through measurement labels. In this post, we’ll walk through how to distinguish between temporary and permanent measurements, and how to get the most out of this system to save time and reduce frustration.
Temporary vs. Saved Labels
When you use the Measure editor in SAMSON, measurements appear immediately and float in your scene. For example:
- Click two atoms to see their distance.
- Click three atoms to see the angle between them.
- Click four atoms to see the torsion (dihedral angle).
These visual cues are extremely useful, but by default, only the last measurement stays visible. So if you click on a new bond or atom, the previous measurement disappears.
To avoid losing your measurements, press Enter to save them as labels. This small step turns a temporary measurement into a part of your document that you can refer back to, even after restarting SAMSON.
Why Save Labels?
Saving your measurements as labels gives you access to several important features:
- Persistence: Measurement data stays intact within your .sam or .samx project files.
- Visibility Control: Labels obey zoom-dependent visibility rules so your workspace stays clean and legible.
- Data Access: You can select any saved label and use the Inspector to review which atoms it refers to.
- Customization: You can tweak line colors, font size, angle plane visibility, and much more for each label.
How to Save and Customize Labels
After making a measurement, simply press Enter. The measurement will be converted to a label in your document. Once saved, you can:
- Modify its visibility and appearance using the Inspector.
- Double-click on text fields in the Inspector to reset colors to default.
- Click the
button next to Text color to clear color changes. - Set different fonts for improved clarity.
Pro Tip: Customize Preferences
You can also use Preferences > Rendering > Labels to set the display style for future labels, such as the number of decimal places or default font.
Conclusion
Working with atom-level measurements doesn’t have to be repetitive. By saving measurements as labels and tweaking their appearance, you can focus more on analysis and less on guesswork. It’s a small habit with a big payoff.
To explore this feature further, check out the full documentation on Measuring in SAMSON.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at www.samson-connect.net.