When a molecular system moves through a trajectory, the feature you want to study can drift out of view. You can pause to reposition the camera, but repeated adjustments interrupt the visual flow and make it harder to compare motion across frames. In SAMSON, the Follow atoms animation can keep a selected part of the system in view while the animation plays.
The key idea is that the camera tracks the geometric center of the atoms selected when you create the animation. The camera target moves with that center, and the camera position moves as well, preserving the vector between the target and the camera. In other words, the camera follows the selected atoms while maintaining its relative viewing position.
Choose what the camera should follow
Start by selecting the atoms that represent the motion you care about. The scope of this selection matters: if you select an entire system, the camera tracks the geometric center of that entire selection. If your question concerns a particular domain or other moving part, selecting the atoms in that part makes the camera follow its center instead.
Before creating the effect, orient the view the way you want it to look. This establishes the camera position for the animation’s start frame. Then choose the start frame in the Animator’s Track view and double-click Follow atoms in the Animator’s Animation panel. Set the end frame to cover the portion of the trajectory you want to present.
Between the start and end keyframes, the target follows the selected atoms’ geometric center. The camera’s starting position comes from the current view; at the end, the camera moves with the atom system while keeping the target-to-camera vector constant. You can move the animation’s start and end frames later if you need to adjust the time range.
Make the selection serve the story
For a useful camera-following view, think about what a viewer needs to keep oriented. A selection that is too broad may follow the overall system and leave a local movement less prominent. A focused selection can keep a moving region near the center of the view. This does not change the underlying trajectory; it changes what the camera tracks while you present it.
It is also worth checking the camera orientation before you create the animation. Follow atoms preserves the camera’s relative position to its target; it is not described as an automatic way to choose a new viewing angle. If the initial view obscures the feature, the camera can continue following it from that same relative direction.
Adjust the view without losing the tracking target
You can adjust camera position with the animation controllers. The target, however, remains at the geometric center of the selected atoms. This distinction is useful when you want to change the viewing position while keeping the tracked group centered.
By default, camera animations apply to the active camera. If you need a different behavior, inspect the animation and change Apply to active camera. You can also inspect Keep camera upwards. Camera positioning may behave differently depending on whether the grid is on or off; when this option is checked, the animation’s behavior depends on the grid state.
In short: select the atoms whose motion matters, set a suitable starting view, create Follow atoms at the desired start frame, and choose an end frame. The result is a camera that tracks the selected group’s center without requiring you to manually chase it through the animation.
Read the Follow atoms documentation to learn more.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.