When studying molecular systems, a common task is to analyze how a structure evolves over time. Equally essential is the ability to retrace and visualize these changes backwards—whether to better understand conformational transitions, double-check simulations, or prepare smooth looping animations for presentations.
The Play Reverse Path animation in SAMSON addresses this need with a simple solution that lets you visually reverse a recorded molecular path—frame-by-frame or as part of a synchronized multi-path setup. This feature is especially helpful for molecular modelers working with reaction trajectories, conformational switches, or any process that benefits from forwards and backwards dynamics visualization.
Why reverse playback matters
Imagine you’ve simulated a molecular association or transformation and now want to visualize how the system deconstructs—each bond unwinding, each molecule retracting into its initial conformation. Having to manually flip that trajectory would be tedious. Instead, SAMSON offers an intuitive way to play the entire path backwards, without altering the original data.
Getting started with ‘Play Reverse Path’
This animation effect is straightforward to set up:
- First, select a Path node in the data graph. This node represents a previously stored trajectory of molecular or conformational motion between frames.
- Then, double-click Play reverse path in the Animation panel of the Animator.
The animation will begin to play your selected trajectory in reverse between the two keyframes. You can easily adjust the keyframe positions on the timeline to fit the desired playback duration.
Synchronized multi-path playback
Need to reverse multiple coordinated paths across a protein complex or multiple molecular entities? You’re in luck. Just select multiple paths before adding the animation, and SAMSON will synchronize their reversed playback automatically. This capability is useful when simulating complex assemblies or disassemblies where multiple parts move simultaneously.
Smoothing and interpolation
What if the number of animation frames doesn’t match the number of recorded path frames? SAMSON smoothes the motion by default so playback remains continuous and visually pleasing. However, you can disable this smoothing through the Inspector if you prefer to keep the trajectory exactly as captured.
You can also shape the behavior of the animation by adjusting the Easing curve. Whether you want to accelerate the motion at the beginning or decelerate towards the end, SAMSON gives you control over the timing through interpolation options.
Visual example
Here’s an example from the documentation showing a reversed playback of a molecular path:
Conclusion
The Play Reverse Path animation effect is a powerful yet easy-to-use tool for retracing molecular movements. Whether you’re refining presentations, analyzing complex events, or preparing cyclic trajectory demonstrations, the ability to walk backward through your data offers clarity and flexibility.
To explore more about this feature and see detailed usage examples, visit the official documentation: Play Reverse Path documentation.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at https://www.samson-connect.net.