A molecular scene can become difficult to read when every structure, label, or visual element stays visible throughout a presentation. Hiding an element instantly may solve the clutter, but it can also make a change feel abrupt. The Disappear animation offers a gradual alternative: selected nodes become increasingly transparent over time.
This is useful when you want to direct attention from one part of a molecular model to another, or make a visual transition feel less sudden. The key is to choose the right nodes and plan the timing before adjusting the animation.
Choose the right target
Start by selecting the nodes you want to fade. Disappear works with nodes that have a transparency attribute, including structural models, visual models, meshes, and labels. The distinction between individual atoms and their structural model matters: atoms and bonds do not have their own opacity attribute. To change their transparency, apply the animation to the structural model containing them.
This is a useful first check if an animation seems not to produce the gradual fade you expect. For a node without a transparency attribute, Disappear behaves similarly to Hide, rather than progressively changing opacity. In other words, selecting the model that carries the transparency property is essential when you want atoms and bonds to fade together.
Use the four keyframes to shape the transition
After choosing the nodes, double-click Disappear in the Animation panel of the Animator. Its four keyframes define a clear sequence:
- Between keyframes 1 and 2: the selected nodes remain fully opaque.
- Between keyframes 2 and 3: they progressively become more transparent.
- Between keyframes 3 and 4: they remain fully transparent.
That means the fade is concentrated in the middle interval, not spread evenly across all four keyframes. If the fade feels too early, too late, or too brief in your presentation, move the keyframes to adjust when the transition starts and how much time it occupies. The keyframes can be moved as needed.
Make the fade serve the explanation
Before adding the animation, decide what the viewer should notice before and after the fade. For example, you might keep a structural model visible while explaining it, then let it fade so another selected element can take focus. The fade changes what is visible in the presentation; it is not a substitute for changing or removing the molecular structure itself.
For a more deliberate pace, consider the time available for the explanation. A short fade can help clear a scene quickly, while a longer fade gives the viewer more time to follow the transition. The documentation does not prescribe one timing for every scene, so use the keyframe positions to suit your sequence.
You can also modify the easing curve to change how parameters are interpolated between frames. This gives you another way to tune the character of the transition without changing which nodes are selected. If the fade’s timing is right but its progression does not feel appropriate, the easing curve is the setting to explore.
A quick troubleshooting checklist
- No gradual fade? Check whether the selected node has a transparency attribute.
- Atoms or bonds are not fading individually? Apply the animation to their structural model.
- The fade happens at the wrong moment? Move the keyframes to reposition the opaque, fading, and transparent intervals.
- The progression feels off? Adjust the easing curve.
For the exact setup steps and related animation details, see the Disappear animation documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.