A static molecular structure can be difficult to explain. A small, controlled movement can help viewers inspect a group of particles and make an animation feel more intentional—but creating that motion by repositioning particles frame by frame can become a distraction from the science.
In SAMSON, the Rock animation offers a focused option: it makes a selected group of particles rock around the group’s geometric center. The movement takes place around a vector that passes through the centroid and is collinear with the Z-axis. That definition is useful when choosing the right animation: Rock provides a particular centered, Z-axis-aligned motion, rather than an arbitrary rotation around any axis.
Set up the motion in three steps
- Select the particles. In the molecular document, select the group you want to animate. The selection defines which particles perform the movement, so check it before adding the effect.
- Add Rock. In the Animator’s Animation panel, double-click the Rock animation effect. The selected group will perform the rocking movement between the animation’s two keyframes.
- Place the keyframes. Move the animation’s keyframes as needed to set where the movement occurs in your presentation. The keyframes can be moved later, so you can adjust the timing as you refine the surrounding content.
Choose Rock for the motion you actually need
It helps to decide what the animation should communicate before adding it. Rock is a good fit when the aim is to give a selected group a rocking movement while keeping the motion centered on that group’s geometric center. The centroid-based axis also gives the movement a clear reference point, rather than making it appear to pivot around an unrelated location.
The axis matters too. Because Rock’s movement is around a vector collinear with the Z-axis, it may not match a presentation that requires rotation around a different axis. SAMSON also documents a Rotate animation, which you can consider when a different kind of rotational movement is needed. For other tasks, related options include Hold atoms and Move atoms.
Refine the transition, not just the pose
The animation’s feel depends not only on its keyframes but also on how the parameters are interpolated between frames. You can change that interpolation by modifying the Easing curve. If the movement feels too abrupt or too gradual for the presentation, review the easing and keyframe placement together. These adjustments help you shape the transition without changing the basic purpose of the Rock effect.
A practical review is to check three things: whether the intended particles are selected, whether the animation occupies the right part of the timeline, and whether the movement reads clearly at the chosen easing. This keeps the setup focused and makes it easier to spot whether the issue is the selection, timing, or the kind of motion itself.
For a concrete example, see 2BRD – Rock animation on SAMSON Connect. To follow the documented workflow and learn more about the effect, visit the Rock animation documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.