When a molecular system moves, a carefully framed view can quickly become unhelpful: the region you want to study drifts toward the edge of the screen, or disappears from view altogether. Repositioning the camera by hand can interrupt the work and make it harder to follow a trajectory. In SAMSON, the Follow atoms animation addresses this by moving the camera with a selected set of atoms.
The key idea is that the camera follows the geometric center of the atoms selected when you create the animation. The camera target moves with that center, while the camera position moves too, preserving the vector between the target and the camera. In practical terms, the view travels with the selected region instead of staying fixed in space.
Choose what the camera should follow
Start by selecting the atoms that define the part of the system you want to keep in view. This choice matters: the animation follows the geometric center of the specified atoms, not necessarily one particular atom or a visually prominent feature. A selection that represents the moving region of interest can make the resulting shot easier to interpret.
For example, if you are examining a moving part of a larger structure, selecting atoms from that part gives the camera a reference that moves with it. The animation is useful when you want to observe motion over time without repeatedly interrupting playback to recenter the view.
Set up the shot before creating the animation
- Select the atoms you want the camera to follow.
- Orient the view and camera as you want them to appear at the beginning of the shot.
- In the Animator’s Track view, choose the animation’s start frame.
- In the Animator’s Animation panel, double-click Follow atoms.
- Set the end frame to cover the interval you want to show.
The current camera position is used at the start frame. At the end frame, the camera follows the selected atom system’s movement while keeping the camera-to-target vector constant. You can move the animation’s start and end frames later if you need to change its timing.
What this animation does—and does not do
Follow atoms keeps the camera target at the geometric center of the specified atoms. It does not mean that the camera independently tracks every atom, or that the target can be freely repositioned while the animation is running. You can adjust camera position using the animation controllers, but the target remains at the selected atoms’ geometric center.
This distinction is useful when planning a presentation: choose the atom selection to define the point that should remain centered, then set the initial camera orientation to establish the view you want. If you instead want the camera to look toward atoms without following their movement in the same way, SAMSON also provides a separate Look at atoms animation.
Check the camera settings
By default, camera animations apply to the active camera. If you need to change this, inspect the animation and adjust Apply to active camera. The Keep camera upwards option can also affect how camera positions are defined in relation to whether the grid is on or off. If the camera’s orientation behaves differently than expected, inspect this setting and check the grid state as part of your setup.
A helpful workflow is to preview the animation from its start to end frame before using it in a presentation or recording. Confirm that the selected region remains framed as intended, and adjust the initial view, selection, or animation timing if needed. Because the target follows the selection’s geometric center, changes in the shape or arrangement of those atoms can also change where that center lies.
For the complete instructions, see the Follow atoms animation documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.
