When creating molecular animations, it’s common to focus on the dynamics of a specific region of a system — maybe a ligand binding site, an active pocket, or a flexible loop. However, one common frustration is keeping that region consistently visible during the motion. Either the structure drifts outside the field of view, or the interesting part moves too much to follow easily. SAMSON offers a practical solution to this issue: the Follow atoms animation effect.
This tool allows the camera to dynamically track selected atoms during an animation, maintaining a constant distance and keeping them centered in view. It’s especially useful when analyzing large trajectories or regions involved in conformational changes.
What does ‘Follow atoms’ do exactly?
Once you select a group of atoms and apply the Follow atoms animation effect at two frames — the starting and the ending frames — SAMSON will calculate how the camera should move so that it continuously tracks the geometric center of the selected atoms. Both the target of the camera and the position of the camera are updated, preserving their relative vector. This ensures that the camera maintains the same angle and distance with respect to the moving region.
This subtle but powerful behavior can improve trajectory presentations by:
- Keeping the region of interest always in view without manual camera adjustments
- Creating smoother and clearer animations to study molecular dynamics
- Saving time when preparing multiple animations of the same region
How to use the ‘Follow atoms’ animation
Here’s a step-by-step overview:
- Select the atoms you want to track: use the selection tools to highlight the relevant region (e.g., a ligand or loop).
- Adjust the view/camera to how you’d like the animation to begin.
- Open the Animator Track View and position the time cursor on the desired starting frame.
- In the Animation panel, double-click on
Follow atoms. - Set the end frame and adjust timing as needed.
You can always modify or move the start and end keyframes later as your animation evolves.
More control when needed
The animation parameters include practical options such as:
- Apply to active camera: Determines which camera the effect controls. This lets you animate different views for parallel comparisons.
- Keep camera upwards: Helps maintain a consistent orientation, especially when toggling grid visibility.
These settings give you finer control over how the animation appears, and you can inspect them at any time.
Refining the view
If you’d like to manually refine the camera position during the animation, you can use animation controllers to adjust the position, while the target point remains locked on the selected atoms’ geometric center. This is useful when you want to zoom in or rotate slightly while still tracking the region of interest.
This capability complements other camera animations available in SAMSON like Look at atoms, which can be used to orient the camera at specific scenes without following dynamic motion.
If you ever found yourself manually adjusting the camera in every frame just to keep a binding site visible, this feature is definitely worth trying.
To learn more, visit the official documentation page: Follow atoms – SAMSON Documentation
SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at https://www.samson-connect.net.