Struggling to manage animation visibility? Here’s how NSL makes it smoother.

When managing molecular animations in SAMSON, one common frustration is losing track of what’s visible and what’s not. You might be aligning molecular events across time, toggling components on and off for clarity, or preparing a story for presentation. But you suddenly realize: Why is this animation not behaving as expected? 🤯

Good news: the Node Specification Language (NSL) has clear, intuitive attributes that make managing visibility in animation nodes much easier. In particular, visibilityFlag and visible provide powerful, distinct ways to fine-tune what your audience sees—and doesn’t see—within your animations.

Understanding an.vf and an.v

Let’s begin with a quick primer. In NSL, the an prefix is used for attributes related specifically to animation nodes. Within this animation attribute space, you can control aspects that are inherited from the general node attribute space.

Two of the most helpful attributes in this context are:

• an.vf (visibilityFlag) – defines whether the visibility of a node can be changed interactively (e.g., through the GUI).
• an.v (visible) – indicates whether the animation node is currently visible or hidden in the viewport.

These attributes are Boolean, meaning they accept just two values: true and false. Their simplicity is deceptive—used well, they can help untangle even complex visual setups.

Real-world example

Suppose you’re working on a molecular dynamics animation showing ligand binding over time. At certain frames, you want to emphasize the movement of the ligand, hiding the rest of the environment to highlight interaction hotspots.

Instead of manually toggling each element, you can streamline with a quick NSL query:

This returns all animation nodes that are hidden, but whose visibility can still be controlled interactively. From there, you can make focused adjustments or script visibility changes in batch.

Why distinguish between visible and visibilityFlag?

The distinction might seem subtle, but it’s very useful:

• an.v returns true if something is currently visible, regardless of why.
• an.vf helps determine if visibility is locked—useful when collaborating or when animations are finalized.

This can help you avoid confusion in shared projects where visibility toggles might be restricted due to context or intentional visibility locks.

Combining queries for better insight

NSL allows logical combinations. Need all visible nodes that can’t be hidden or shown interactively?

This becomes especially useful for debugging visibility states across frames or comparing animation stages.

Even though this functionality might appear simple at first glance, it creates a lot of flexibility for presenting complex molecular dynamics with precision and consistency.

To dive deeper into these and other animation node attributes, head to the original documentation page: NSL – Animation Attributes.

SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at https://www.samson-connect.net.