One frequent challenge in molecular modeling is effectively visualizing and communicating the motions of molecules. Whether you’re studying a ligand as it exits a binding site or analyzing a protein conformational pathway, being able to show a trajectory in reverse can be just as important as playing it forward.
If you’re using SAMSON, the integrative platform for molecular design, you may already know how to create animations of molecular paths. But did you know you can easily reverse those animations—allowing your molecule’s path to play backward between two keyframes?
Why Visualizing Reverse Trajectories Matters
Often, you aren’t just interested in how a process happens—you want to see how it unfolds if it goes the other way. For example:
- Retracing a ligand’s exit pathway from a protein pocket
- Visualizing how a molecule might return to its initial state for loop animations
- Comparing forward and backward transitions for pathways involving cyclic conformational changes
The Play reverse path animation feature in SAMSON lets you do just that.
Quick Setup in SAMSON
To start:
- Select a path node—which stores a trajectory in SAMSON—that you want to reverse.
- In the Animation panel of the Animator, double-click on Play reverse path. This will add the animation effect to your presentation.
- The entire path will now play in reverse between the two designated keyframes. You can always adjust these keyframes to control the timing and section of the animation.
Synchronizing Multiple Paths
Need to visualize multiple components? The Play reverse path animation syncs multiple paths automatically if you select more than one at a time. This is useful, for example, in multi-chain proteins or protein-ligand systems where relative movement matters.
Fine-Tuning with Easing
For smoother transitions or dramatic emphasis, animation timing can be fine-tuned using different easing curves. These change how motion is interpolated between frames—for example, gradually accelerating or decelerating molecular movement. The Inspector lets you access and modify this at any time.
Smoothing vs. Raw Trajectories
If the number of frames in your animation does not match the number of frames in the path, SAMSON smooths the animation by default. For precise frame-by-frame replay (e.g., in tutorials or data verification), you can turn off smoothing from the Inspector.
A Visual Example
Conclusion
Whether you’re preparing a presentation, exploring a simulated molecular event, or simply want a clearer view of molecular dynamics, reversing the trajectory animation adds flexibility and insight to your analysis.
To try this feature in SAMSON, or to learn more about how to control animations, visit the Play reverse path documentation page.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at https://www.samson-connect.net.