When creating molecular animations, getting the motion of atoms just right can be a challenge, especially when you want some atoms to stay perfectly still while others move. Whether you’re crafting a docking movie or visualizing a ligand binding process, unintended atom motion between frames can distract from the message you are trying to convey.
This is where the Hold atoms animation effect in SAMSON comes in handy. This small but powerful tool lets you lock selected atoms in place between two keyframes, bringing clarity and intent to your presentation.
Why Holding Atoms Matters
Let’s say you’re animating a protein-ligand docking scene. You may want to move the ligand toward the binding site while keeping the receptor protein completely still to highlight the docking process. But if both protein and ligand are controlled by default animations, even slight, unintended movements in the protein’s position can mislead your viewers.
With the Hold atoms effect, you can prevent this. It lets you select specific atoms — for example, the protein — and freeze their positions in space between two selected animation frames. The rest of the scene can continue to animate normally, helping you tell a clear story about the moving parts in your system.
How to Use the “Hold atoms” Animation
- Select the atoms you want to hold in place. You can do this using SAMSON’s selection tools.
- Then, open the Animation panel inside the Animator.
- Double-click on the Hold atoms option. This inserts an animation keyframe pair and applies the hold effect to your selected atoms.
- Now you can freely re-position surrounding atoms or molecules while ensuring the selected atoms stay fixed between those frames.
And yes — you can always adjust the position of the keyframes later. This flexibility makes it useful for refining the timing of different animation components.
Examples in Action
Need examples or inspiration? Some publicly available presentations on SAMSON Connect use this effect, such as:
Below, you can see a simplified example where atoms are both moved and held using animations:
This effect can be a small but impactful detail in any molecular presentation. It helps you guide your audience’s focus, emphasize specific molecular interactions, and avoid visual noise.
To learn more, visit the full documentation page for the Hold atoms animation effect.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON here.