When analyzing molecular simulations or transitions between conformations, it’s often important to observe not just how a system evolves forward in time—but also how it retraces its steps. Whether you’re investigating conformational cycles, analyzing equilibration processes, or simply making presentations more dynamic, playing a molecular path in reverse can provide important insights.
In SAMSON, the Play reverse path animation makes it straightforward to replay a molecular path backward between two keyframes. Let’s explore how this feature can help you analyze and communicate molecular mechanisms more effectively.
Why reverse animation is useful
Simulations often generate long trajectories of motions—for example, protein folding/unfolding or ligand binding and unbinding. While the forward movement might represent the natural evolution of the system, reversing the animation can highlight symmetries, detect bottlenecks in motions, or simply help in better visual storytelling during presentations or classes.
How to use the Play reverse path animation
Reversing paths in SAMSON is simple and intuitive:
- Select a path node in your SAMSON Document. This could be a trajectory you’ve imported or built manually.
- Open the Animator (via the Animation panel).
- Double-click on the Play reverse path animation effect to add it.
- Molecules will now move backwards along the chosen path between two keyframes.
If you’ve selected multiple paths, SAMSON synchronizes them automatically—helpful for comparing different molecular regions or aligning separate conformational changes across parts of a system.
Smoothing and keyframe control
SAMSON offers built-in path smoothing: if the number of frames in your animation doesn’t match the path’s frame count, the movement is interpolated. This ensures a visually continuous motion. However, if you prefer a direct frame-by-frame playback, you can disable smoothing in the Inspector.
You can adjust the position of keyframes freely. This allows full control over when in your animation the reverse playback begins and ends.
Fine-tuning with easing curves
To control the dynamics of how transitions occur, try editing the Easing curve. These curves define how motion speeds up or slows down between keyframes—ideal for making animations look more “natural” or for emphasizing specific steps in a conformational change.
Visual example
Here’s what a Play reverse path animation looks like in action:
Conclusion
The Play reverse path feature in SAMSON isn’t just about aesthetics—it enables a deeper understanding of molecular processes by letting you explore them from a different angle. Whether you’re creating educational animations or trying to spot structural details during analysis, it’s a helpful addition to your molecular modeling toolkit.
To learn more, visit the full documentation page here: https://documentation.samson-connect.net/users/latest/animations/play-reverse-path/
SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at https://www.samson-connect.net.