When working with molecular trajectories, it’s often necessary to analyze not just how a system evolves forward, but also what happens when the process is reversed. For instance, in conformational studies or reaction reversibility checks, playing a path backward can significantly help understand the system’s behavior.
If you’re using SAMSON for molecular design and modeling, there’s a built-in way to do exactly that — no scripting or exporting needed. Whether you’re studying protein folding, cyclic reactions, or docking/unbinding events, visualizing a reverse path might just offer the insight you’re missing.
What is the ‘Play reverse path’ animation?
The Play reverse path animation in SAMSON allows users to replay a molecular path (or several paths) in the reverse direction between two keyframes in a presentation. It’s designed to help you observe backward molecular changes, examine reversibility, or loop a transition by combining it with its forward version. You can even sync the backward motion across multiple selected paths.
This comes in especially handy for anyone trying to:
- Compare forward and reverse dynamics visually
- Create smoother animation loops of cyclic processes
- Investigate unbinding routes in reverse
How to Add the Animation
The process is straightforward:
- Select the Path node(s) in your SAMSON document. Each path represents a molecular transition or trajectory.
- Go to the Animator interface, inside the Animation Panel.
- Double-click on Play reverse path to insert the animation for the selected path(s).
- Two keyframes will appear on the timeline, defining the animation period. The selected molecular path(s) will be played in reverse between these frames.
You can manually move the keyframes to adjust the timing of the animation.
What if My Path Length Doesn’t Match Frame Count?
When the number of frames in the animation doesn’t perfectly match the number of conformations (or states) in the path, the playback will smooth the transitions by interpolating positions. If you need precise replay without interpolation, you can disable smoothing using the Inspector.
Customize the Interpolation
To change how the molecular parameters (positions, angles, etc.) evolve over time, you can modify the easing curve. This gives you control over the pacing of the animation, allowing for linear, accelerating, or decelerating motion profiles. It’s particularly helpful for presentations or visual storytelling.
Bonus: Create a Seamless Loop
If you chain a forward Play path animation and a reverse one end-to-end, you can build a seamless loop of a molecular transition. This is an engaging way to represent repeated molecular behavior in teaching material or presentations.
To learn more about reverse path animations, visit the full documentation at https://documentation.samson-connect.net/users/latest/animations/play-reverse-path/
SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at https://www.samson-connect.net.