When a molecular trajectory plays, the region you wanted to study can drift out of view. A common reaction is to move the camera repeatedly, but that can make it harder to compare the motion or keep a presentation visually consistent. In SAMSON, the Look at atoms animation offers a simpler approach: keep the camera position fixed while its target follows a selected group of atoms.
What moves—and what stays put?
This distinction is useful when planning a molecular animation. With Look at atoms, the camera does not travel through space. Instead, its target point moves with the geometric center of the atoms selected when the animation is created. As those atoms move, the view continues to look toward them.
For example, if you want to watch a moving region while leaving the viewpoint in place, this animation can keep that region in view without introducing camera-position changes. It is especially helpful when the motion of the molecule is already the main thing you want the viewer to follow.
Set up the view before adding the animation
The order of operations matters because the animation uses the atoms selected at creation time and the camera position you establish beforehand.
- Select the atoms you want the camera to keep looking at. Choose a group that represents the feature you want to follow, rather than selecting the whole system by habit.
- Orient the view and position the camera as you want it to appear in the animation. Look at the subject from the intended angle before adding the effect.
- Choose a start frame in the Animator’s Track view.
- Add Look at atoms by double-clicking the effect in the Animator’s Animation panel.
- Set the end frame to cover the portion of the trajectory or presentation you want to show.
Between the start and end keyframes, the camera target follows the geometric center of the specified atoms. The current camera position is used at both ends. You can move the animation’s start and end frames later if you need to change when the effect begins or finishes.
Keep the selection and camera behavior in mind
Because the target follows the selected atoms’ geometric center, the choice of atoms affects the result. A selection spread across a large structure may produce a center that is not the particular feature you want to emphasize. Selecting a more focused group can make the camera’s tracking behavior easier to interpret.
Camera animations are applied to the active camera by default. If your scene uses more than one camera, inspect the animation and review Apply to active camera to control which camera the effect applies to.
The Keep camera upwards option can also affect how the animation behaves depending on whether the grid is switched on or off. If the view’s orientation seems different than expected, inspect this setting along with the grid state.
Adjusting the view later
You can use the animation controllers to adjust the camera position. The target, however, remains at the geometric center of the specified atoms. In other words, you can refine where the camera is positioned without changing which selected group the animation tracks.
Use Look at atoms when the viewpoint should stay put but the subject should remain the focus. If you instead need the camera itself to move with atoms, see the separate Follow atoms animation.
For the full procedure and property details, see the Look at atoms documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.