A crowded molecular scene can be difficult to explain. When several structures, meshes, or labels are visible at once, viewers may struggle to tell which object matters first. Hiding objects until they are needed is one option; fading them in can make the order of a presentation easier to follow.
In SAMSON, the Appear animation progressively reveals selected nodes. It is useful when you want a structure or other supported object to enter the viewer’s attention gradually rather than appear all at once. For example, you might introduce a structural model after showing the surrounding scene, or bring in a label only when its subject is being discussed.
Apply the animation to the right object
Start by selecting the nodes you want to reveal. Then, in the Animator, open the Animation panel and double-click Appear. The animation can be applied to nodes that have a transparency attribute, including structural models, visual models, meshes, and labels.
One distinction is especially useful when working with molecular structures: individual atoms and bonds do not have their own opacity attribute. Their structural models do. So, if your goal is to fade in atoms and bonds, apply Appear to the structural model that contains them—not to the individual atoms or bonds. This helps avoid the confusing result of selecting the visible molecular details while expecting their transparency to change.
For nodes without a transparency attribute, Appear behaves similarly to the Show animation. If you specifically need a transparency change, check that the selected node type supports it.
What the four keyframes do
The animation has four keyframes that divide the reveal into three stages:
- Between keyframes 1 and 2, the selected nodes are fully transparent.
- Between keyframes 2 and 3, they progressively appear as their transparency decreases.
- Between keyframes 3 and 4, they remain fully opaque, with no transparency.
You can move the keyframes to adjust when each stage occurs. This gives you a practical way to control the pacing: allow a pause before the object appears, make the fade occupy more or less of the sequence, or leave time for viewers to inspect the fully visible result. The easing curve controls how the animation parameters are interpolated between frames, so it is another place to adjust the feel of the transition.
A simple planning approach
Before adding the effect, decide what the viewer should notice first. Select only the nodes that serve that moment, apply Appear, and then arrange the keyframes so the reveal has enough time to be understood. If the scene contains several objects, separate their appearances into distinct moments rather than fading everything in together. A gradual reveal is most useful when it reduces visual competition—not simply because an animation is available.
Preview the sequence and check two things: whether the intended object is invisible before its reveal, and whether it reaches full opacity in time for the explanation that follows. If a molecular structure does not fade as expected, verify that the animation is applied to its structural model. You can adjust the keyframes at any time.
For details and the illustrated example, see the Appear animation documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.